98-539: The Stuart Sapphire is a blue sapphire that forms part of the British Crown Jewels . It weighs 104 carats (20.8 grams) and is believed to have originated from Asia, potentially present-day Afghanistan , Sri Lanka , Myanmar or Kashmir . The early history of the gem is quite obscure, though it probably belonged to Charles II , and was definitely among the jewels that his successor James VII and II took with him when he fled to France after
196-657: A mullion separating them, that open outward with opposing hinges to a terrace or porch, are referred to as a French window . Sometimes these are set in pairs or multiples thereof along the exterior wall of a very large room, but often, one French window is placed centrally in a typically sized room, perhaps among other fixed windows flanking the feature. French windows are known as porte-fenêtre in France and portafinestra in Italy, and frequently are used in modern houses. Double-paned windows have two parallel panes (slabs of glass) with
294-1018: A sash set in a frame in the opening; the sash and frame are also referred to as a window. Many glazed windows may be opened, to allow ventilation , or closed to exclude inclement weather . Windows may have a latch or similar mechanism to lock the window shut or to hold it open by various amounts. Types include the eyebrow window, fixed windows, hexagonal windows , single-hung, and double-hung sash windows, horizontal sliding sash windows , casement windows , awning windows, hopper windows, tilt, and slide windows (often door-sized), tilt and turn windows, transom windows, sidelight windows, jalousie or louvered windows, clerestory windows, lancet windows , skylights , roof windows , roof lanterns , bay windows , oriel windows , thermal, or Diocletian , windows, picture windows, rose windows , emergency exit windows, stained glass windows, French windows, panel windows, double/triple-paned windows, and witch windows . The English language-word window originates from
392-464: A certificate from an independent gemological laboratory attesting to "no evidence of heat treatment". Yogo sapphires do not need heat treating because their cornflower blue color is attractive out of the ground; they are generally free of inclusions , and have high uniform clarity. When Intergem Limited began marketing the Yogo in the 1980s as the world's only guaranteed untreated sapphire, heat treatment
490-399: A dominant red body color. This is generally caused by traces of chromium (Cr ) substituting for the (Al ) ion in the corundum structure. The color can be modified by both iron and trapped hole color centers. Unlike localized ("intra-atomic") absorption of light, which causes color for chromium and vanadium impurities, blue color in sapphires comes from intervalence charge transfer, which is
588-410: A double-hung, or in-line. The inline versions can be made to fold inward or outward. The inward swinging foldup windows can have fixed screens, while the outward swinging ones require movable screens. The windows are typically used for screen rooms, kitchen pass-throughs, or egress. A horizontal sliding sash window has two or more sashes that overlap slightly but slide horizontally within the frame. In
686-453: A friction device to hold the window open against its weight and may have restriction and reversed locking built-in. In the UK, where this type of window is most common, they were extensively installed in high-rise social housing. A tilt and slide window is a window (more usually a door-sized window) where the sash tilts inwards at the top similar to a hopper window and then slides horizontally behind
784-492: A long-standing motif of pointed or rounded window-shapes in ecclesiastical buildings, still seen in many churches today. Peter Smith discusses overall trends in early-modern rural Welsh window architecture: Up to about 1680 windows tended to be horizontal in proportion, a shape suitable for lighting the low-ceilinged rooms that had resulted from the insertion of the upper floor into the hall-house. After that date vertically proportioned windows came into fashion, partly at least as
882-410: A lot of strain due to the high thermal gradient between the flame and surrounding air. To release this strain, the now finger-shaped crystal will be tapped with a chisel to split it into two halves. Due to the vertical layered growth of the crystal and the curved upper growth surface (which starts from a drop), the crystals will display curved growth lines following the top surface of the boule. This
980-519: A millennium before window glass became transparent enough to see through clearly, as we expect now. In 1154, Al-Idrisi described glass windows as a feature of the palace belonging to the king of the Ghana Empire . Over the centuries techniques were developed to shear through one side of a blown glass cylinder and produce thinner rectangular window panes from the same amount of glass material. This gave rise to tall narrow windows, usually separated by
1078-400: A rate of 1 to 100 mm per hour. The alumina crystallizes on the end, creating long carrot-shaped boules of large size up to 200 kg in mass. Synthetic sapphire is also produced industrially from agglomerated aluminum oxide, sintered and fused (such as by hot isostatic pressing ) in an inert atmosphere, yielding a transparent but slightly porous polycrystalline product. In 2003,
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#17328478007761176-503: A respected laboratory such as GIA , Lotus Gemology , or SSEF , is often required by buyers before they will make a purchase. Sapphires in colors other than blue are called "fancy" sapphires. "Parti sapphire" is used for multicolor stones with zoning of different colors (hues), but not different shades. Fancy sapphires are found in yellow, orange, green, brown, purple, violet, and practically any other hue. Gemstone color can be described in terms of hue , saturation , and tone . Hue
1274-537: A response to the Renaissance taste for the high ceiling. Since 1914 the wheel has come full circle and a horizontally proportioned window is again favoured. The spread of plate-glass technology made possible the introduction of picture windows (in Levittown, Pennsylvania , founded 1951–1952 ). Many modern day windows may have a window screen or mesh, often made of aluminum or fibreglass , to keep bugs out when
1372-438: A separation of typically about 1 cm; this space is permanently sealed and filled at the time of manufacture with dry air or other dry nonreactive gas. Such windows provide a marked improvement in thermal insulation (and usually in acoustic insulation as well) and are resistant to fogging and frosting caused by temperature differential. They are widely used for residential and commercial construction in intemperate climates. In
1470-639: A separator ( mullion ). Typically, the cellular window is used for an attic or as a decorative feature, but it can also be a major architectural element to provide the natural lighting inside buildings. A guillotine window is a window that opens vertically. Guillotine windows have more than one sliding frame, and open from bottom to top or top to bottom. EN 12519 is the European standard that describes windows terms officially used in EU Member States. The main terms are: The United States NFRC Window Label lists
1568-417: A variety of shades. Corundum that contains extremely low levels of chromophores is near colorless. Completely colorless corundum generally does not exist in nature. If trace amounts of iron are present, a very pale yellow to green color may be seen. However, if both titanium and iron impurities are present together, and in the correct valence states, the result is a blue color. Intervalence charge transfer
1666-474: A vertical support called a mullion . Mullioned glass windows were the windows of choice among the European well-to-do, whereas paper windows were economical and widely used in ancient China, Korea, and Japan. In England, glass became common in the windows of ordinary homes only in the early-17th century, whereas windows made up of panes of flattened animal horn were used as early as the 14th century. Modern-style floor-to-ceiling windows became possible only after
1764-429: A wall, typically without glazing bars , or glazed with only perfunctory glazing bars ( muntins ) near the edge of the window. Picture windows provide an unimpeded view, as if framing a picture. A multi-lite window is a window glazed with small panes of glass separated by wooden or lead glazing bars , or muntins , arranged in a decorative glazing pattern often dictated by the building's architectural style. Due to
1862-493: Is a door with a jalousie window. A clerestory window is a window set in a roof structure or high in a wall, used for daylighting . A skylight is a window built into a roof structure. This type of window allows for natural daylight and moonlight. A roof window is a sloped window used for daylighting , built into a roof structure. It is one of the few windows that could be used as an exit. Larger roof windows meet building codes for emergency evacuation. A roof lantern
1960-500: Is a multi-paned glass structure, resembling a small building, built on a roof for day or moon light. Sometimes includes an additional clerestory . May also be called a cupola . A bay window is a multi-panel window, with at least three panels set at different angles to create a protrusion from the wall line. An oriel window is a form of bay window. This form most often appears in Tudor-style houses and monasteries. It projects from
2058-442: Is a process that produces a strong colored appearance at a low percentage of impurity. While at least 1% chromium must be present in corundum before the deep red ruby color is seen, sapphire blue is apparent with the presence of only 0.01% of titanium and iron. Colorless sapphires, which are uncommon in nature, were once used as diamond substitutes in jewelry, and are presently used as accent stones. The most complete description of
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#17328478007762156-459: Is a specific change in energy for the electron, and electromagnetic energy is absorbed. The wavelength of the energy absorbed corresponds to yellow light. When this light is subtracted from incident white light, the complementary color blue results. Sometimes when atomic spacing is different in different directions, there is resulting blue-green dichroism . Purple sapphires contain trace amounts of chromium and iron plus titanium and come in
2254-486: Is a type of sapphire that exhibits a star-like phenomenon known as asterism ; red stones are known as "star rubies". Star sapphires contain intersecting needle-like inclusions following the underlying crystal structure that causes the appearance of a six-rayed "star"-shaped pattern when viewed with a single overhead light source. The inclusion is often the mineral rutile , a mineral composed primarily of titanium dioxide . The stones are cut en cabochon , typically with
2352-439: Is added to the flame, causing it to burn slightly hotter. This expands the growing crystal laterally. At the same time, the pedestal is lowered at the same rate that the crystal grows vertically. The alumina in the flame is slowly deposited, creating a teardrop shaped " boule " of sapphire material. This step is continued until the desired size is reached, the flame is shut off and the crystal cools. The now elongated crystal contains
2450-489: Is called padparadscha . Significant sapphire deposits are found in Australia , Afghanistan , Cambodia , Cameroon , China ( Shandong ), Colombia , Ethiopia , India Jammu and Kashmir ( Padder , Kishtwar ), Kenya , Laos , Madagascar , Malawi , Mozambique , Myanmar ( Burma ), Nigeria , Rwanda , Sri Lanka , Tanzania , Thailand , United States ( Montana ) and Vietnam . Sapphire and rubies are often found in
2548-451: Is common practice to heat natural sapphires to improve or enhance their appearance. This is done by heating the sapphires in furnaces to temperatures between 800 and 1,800 °C (1,470 and 3,270 °F) for several hours, or even weeks at a time. Different atmospheres may be used. Upon heating, the stone becomes bluer in color, but loses some of the rutile inclusions (silk). When high temperatures (1400 °C+) are used, exsolved rutile silk
2646-428: Is commonly understood as the " color " of the gemstone. Saturation refers to the vividness or brightness of the hue, and tone is the lightness to darkness of the hue. Blue sapphire exists in various mixtures of its primary (blue) and secondary hues, various tonal levels (shades) and at various levels of saturation (vividness). Blue sapphires are evaluated based upon the purity of their blue hue. Violet and green are
2744-548: Is derived from the Latin word sapphirus , itself from the Greek word sappheiros ( σάπφειρος ), which referred to lapis lazuli . It is typically blue, but natural "fancy" sapphires also occur in yellow, purple, orange, and green colors; "parti sapphires" show two or more colors. Red corundum stones also occur, but are called rubies rather than sapphires. Pink-colored corundum may be classified either as ruby or sapphire depending on
2842-409: Is dissolved and it becomes clear under magnification. The titanium from the rutile enters solid solution and thus creates with iron the blue color. The inclusions in natural stones are easily seen with a jeweler's loupe . Evidence of sapphire and other gemstones being subjected to heating goes back at least to Roman times. Un-heated natural stones are somewhat rare and will often be sold accompanied by
2940-554: Is heavily tilted to the red end of the spectrum, thus tipping the balance to red. Color-change sapphires colored by the Cr + Fe/Ti chromophores generally change from blue or violet-blue to violet or purple. Those colored by the V chromophore can show a more pronounced change, moving from blue-green to purple. Certain synthetic color-change sapphires have a similar color change to the natural gemstone alexandrite and they are sometimes marketed as "alexandrium" or "synthetic alexandrite". However,
3038-432: Is in contrast to natural corundum crystals, which feature angular growth lines expanding from a single point and following the planar crystal faces. Chemical dopants can be added to create artificial versions of the ruby, and all the other natural colors of sapphire, and in addition, other colors never seen in geological samples. Artificial sapphire material is identical to natural sapphire, except it can be made without
Stuart Sapphire - Misplaced Pages Continue
3136-464: Is known as a fanlight, especially in the British Isles. Windows beside a door or window are called side-, wing-, margen-lights, and flanking windows. Also known as a louvered window, the jalousie window consists of parallel slats of glass or acrylic that open and close like a Venetian blind , usually using a crank or a lever. They are used extensively in tropical architecture. A jalousie door
3234-564: Is on public display with the other Crown Jewels in the Jewel House at the Tower of London . The sapphire weighs 104-carat (20.8 g). It is oval-shaped, about 3.8 cm (1.5 in) long and 2.5 cm (1.0 in) wide, and has one or two blemishes but was evidently deemed to be of high value by the Stuarts. At some point a hole was drilled at one end, probably to introduce an attachment by which
3332-416: Is required of any mode of enhancement that has a significant effect on the gem's value. There are several ways of treating sapphire. Heat-treatment in a reducing or oxidizing atmosphere (but without the use of any other added impurities) is commonly used to improve the color of sapphires, and this process is sometimes known as "heating only" in the gem trade. In contrast, however, heat treatment combined with
3430-677: Is thought to be the third-largest star sapphire, and is currently on display at the American Museum of Natural History in New York City . The 182-carat Star of Bombay , mined in Sri Lanka and located in the National Museum of Natural History in Washington, D.C. , is another example of a large blue star sapphire. The value of a star sapphire depends not only on the weight of the stone, but also
3528-408: Is used in situations where light or vision alone is needed as no ventilation is possible in such windows without the use of trickle vents or overglass vents. A single-hung sash window is a window that has one sash that is movable (usually the bottom one) and the other fixed. This is the earlier form of sliding sash window and is also cheaper. A sash window is the traditional style of window in
3626-582: Is used in two ways: a curved top window in a wall or an eyebrow dormer ; and a row of small windows usually under the front eaves such as the James-Lorah House in Pennsylvania. A fixed window is a window that cannot be opened, whose function is limited to allowing light to enter (unlike an unfixed window, which can open and close). Clerestory windows in church architecture are often fixed. Transom windows may be fixed or operable. This type of window
3724-628: The Danish language vindue and Norwegian Bokmål vindu , the direct link to eye is lost, just as for window . The Danish (but not the Bokmål ) word is pronounced fairly similarly to window . Window is first recorded in the early 13th century, and originally referred to an unglazed hole in a roof. Window replaced the Old English eagþyrl , which literally means 'eye-hole', and eagduru 'eye-door'. Many Germanic languages, however, adopted
3822-537: The Glorious Revolution in December 1688. From there it passed to his son, James Stuart (the 'Old Pretender') who bequeathed it to his son, Henry Benedict , known later as Cardinal York, who wore it in his mitre . As the last descendant of James VII and II, the cardinal put the sapphire, along with many other Stuart relics, up for sale. It was purchased by George III in 1807 and returned to
3920-566: The Old Norse vindauga , from vindr 'wind' and auga 'eye'. In Norwegian , Nynorsk , and Icelandic , the Old Norse form has survived to this day (in Icelandic only as a less used word for a type of small open "window", not strictly a synonym for gluggi , the Icelandic word for 'window' ). In Swedish , the word vindöga remains as a term for a hole through the roof of a hut, and in
4018-617: The Star of India , The Star of Adam and the Star of Bombay originate from Sri Lankan mines. Madagascar is the world leader in sapphire production (as of 2007) specifically its deposits in and around the town of Ilakaka . Prior to the opening of the Ilakaka mines, Australia was the largest producer of sapphires (such as in 1987). In 1991 a new source of sapphires was discovered in Andranondambo, southern Madagascar. The exploitation started in 1993, but
Stuart Sapphire - Misplaced Pages Continue
4116-557: The chromium chromophore that creates the red color of ruby, combined with the iron + titanium chromophore that produces the blue color in sapphire. A rarer type, which comes from the Mogok area of Myanmar, features a vanadium chromophore, the same as is present in Verneuil synthetic color-change sapphire. Virtually all gemstones that show the "alexandrite effect" (color change or ' metamerism ') show similar absorption/transmission features in
4214-545: The insulating substrates of special-purpose solid-state electronics such as integrated circuits and GaN -based blue LEDs . Sapphire is the birthstone for September and the gem of the 45th anniversary . A sapphire jubilee occurs after 65 years. Sapphire is one of the two gem-varieties of corundum , the other being ruby (defined as corundum in a shade of red). Although blue is the best-known sapphire color, it occurs in other colors, including gray and black, and also can be colorless. A pinkish orange variety of sapphire
4312-656: The 12.00 carat Cartier sapphire ring at US$ 193,975 per carat, then with a 17.16 carat sapphire at US$ 236,404, and again in June 2015 when the per-carat auction record was set at US$ 240,205. At present, the world record price-per-carat for sapphire at auction is held by a sapphire from Kashmir in a ring, which sold in October 2015 for approximately US$ 242,000 per carat ( HK$ 52,280,000 in total, including buyer's premium, or more than US$ 6.74 million). Sapphires can be treated by several methods to enhance and improve their clarity and color. It
4410-560: The 13th century BC, the earliest windows were unglazed openings in a roof to admit light during the day. Later, windows were covered with animal hide, cloth, or wood. Shutters that could be opened and closed came next. Over time, windows were built that both protected the inhabitants from the elements and transmitted light, using multiple small pieces of translucent material, such as flattened pieces of translucent animal horn, paper sheets, thin slices of marble (such as fengite ), or pieces of glass, set in frameworks of wood, iron or lead. In
4508-631: The Far East, paper was used to fill windows. The Romans were the first known users of glass for windows, exploiting a technology likely first developed in Roman Egypt . Specifically, in Alexandria c. 100 CE, cast-glass windows, albeit with poor optical properties, began to appear, but these were small thick productions, little more than blown-glass jars (cylindrical shapes) flattened out into sheets with circular striation patterns throughout. It would be over
4606-520: The French chemist Auguste Verneuil announced a process for producing synthetic ruby crystals. In the flame-fusion ( Verneuil process ), fine alumina powder is added to an oxyhydrogen flame , and this is directed downward against a ceramic pedestal. Following the successful synthesis of ruby, Verneuil focused his efforts on sapphire. Synthesis of blue sapphire came in 1909, after chemical analyses of sapphire suggested to Verneuil that iron and titanium were
4704-565: The Latin word fenestra to describe a window with glass, such as standard Swedish fönster , or German Fenster . The use of window in English is probably because of the Scandinavian influence on the English language by means of loanwords during the Viking Age . In English, the word fenester was used as a parallel until the mid-18th century. Fenestration is still used to describe
4802-435: The UK and many other parts of Europe. An awning window is a casement window that is hung horizontally, hinged on top, so that it swings outward like an awning . In addition to being used independently, they can be stacked, several in one opening, or combined with fixed glass. They are particularly useful for ventilation. A hopper window is a bottom-pivoting casement window that opens by tilting vertically, typically to
4900-529: The UK, double-paned and triple-paned are referred to as double- glazing and triple-glazing. Triple-paned windows are now a common type of glazing in central to northern Europe. Quadruple glazing is now being introduced in Scandinavia. A hexagonal window is a hexagon -shaped window, resembling a bee cell or crystal lattice of graphite. The window can be vertically or horizontally oriented, openable or dead. It can also be regular or elongately-shaped and can have
4998-407: The UK, these are sometimes called Yorkshire sash windows, presumably because of their traditional use in that county. A casement window is a window with a hinged sash that swings in or out like a door comprising either a side-hung, top-hung (also called "awning window"; see below), or occasionally bottom-hung sash or a combination of these types, sometimes with fixed panels on one or more sides of
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#17328478007765096-733: The United Kingdom from Italy. On the Imperial State Crown of Queen Victoria , the jewel took pride of place at the front of the circlet, just below the Black Prince's Ruby . In 1909, during the reign of Edward VII , it was moved to the back of the crown to make way for the 317-carat (63.4 g) Cullinan II diamond; it still occupies that position in the back of the Imperial State Crown made in 1937 (a copy of Victoria's) and used by Charles III . The Stuart Sapphire
5194-445: The United Kingdom, and many other places that were formerly colonized by the UK, with two parts (sashes) that overlap slightly and slide up and down inside the frame. The two parts are not necessarily the same size; where the upper sash is smaller (shorter) it is termed a cottage window . Currently, most new double-hung sash windows use spring balances to support the sashes, but traditionally, counterweights held in boxes on either side of
5292-683: The area of Franklin, North Carolina . The sapphire deposits of Kashmir are well known in the gem industry, although their peak production took place in a relatively short period at the end of the nineteenth and early twentieth centuries. These deposits are located in the Paddar Valley of the Jammu region of Jammu and Kashmir in India. They have a superior vivid blue hue, coupled with a mysterious and almost sleepy quality, described by some gem enthusiasts as ‘blue velvet”. Kashmir-origin contributes meaningfully to
5390-481: The arrangement of windows within a façade , as well as defenestration , meaning 'to throw out of a window'. The Romans were the first known to use glass for windows, a technology likely first produced in Roman Egypt , in Alexandria c. 100 AD . Presentations of windows can be seen in ancient Egyptian wall art and sculptures from Assyria. Paper windows were economical and widely used in ancient China, Korea, and Japan. In England, glass became common in
5488-588: The biggest problem the Yogo mine faced was not competition from heated sapphires, but the fact that the Yogo stones could never produce quantities of sapphire above one carat after faceting. As a result, it has remained a niche product, with a market that largely exists in the US. Lattice ('bulk') diffusion treatments are used to add impurities to the sapphire to enhance color. This process was originally developed and patented by Linde Air division of Union Carbide and involved diffusing titanium into synthetic sapphire to even out
5586-415: The blue color. It was later applied to natural sapphire. Today, titanium diffusion often uses a synthetic colorless sapphire base. The color layer created by titanium diffusion is extremely thin (less than 0.5 mm). Thus repolishing can and does produce slight to significant loss of color. Chromium diffusion has been attempted, but was abandoned due to the slow diffusion rates of chromium in corundum. In
5684-466: The body color, visibility, and intensity of the asterism. The color of the stone has more impact on the value than the visibility of the star. Since more transparent stones tend to have better colors, the most expensive star stones are semi-transparent "glass body" stones with vivid colors. On 28 July 2021, the world's largest cluster of star sapphires, weighing 510 kg (1,120 lb), was unearthed from Ratnapura, Sri Lanka. This star sapphire cluster
5782-433: The cause of the blue color. Verneuil patented the process of producing synthetic blue sapphire in 1911. The key to the process is that the alumina powder does not melt as it falls through the flame. Instead it forms a sinter cone on the pedestal. When the tip of that cone reaches the hottest part of the flame, the tip melts. Thus the crystal growth is started from a tiny point, ensuring minimal strain. Next, more oxygen
5880-1272: The causes of color in corundum extant can be found in Chapter ;4 of Ruby & Sapphire: A Gemologist's Guide (chapter authored by John Emmett, Emily Dubinsky and Richard Hughes). Sapphires are mined from alluvial deposits or from primary underground workings. Commercial mining locations for sapphire and ruby include (but are not limited to) the following countries: Afghanistan , Australia , Myanmar / Burma , Cambodia , China , Colombia , India , Kenya , Laos , Madagascar , Malawi , Nepal , Nigeria , Pakistan , Sri Lanka , Tajikistan , Tanzania , Thailand , United States, and Vietnam . Sapphires from different geographic locations may have different appearances or chemical-impurity concentrations, and tend to contain different types of microscopic inclusions. Because of this, sapphires can be divided into three broad categories: classic metamorphic, non-classic metamorphic or magmatic, and classic magmatic. Sapphires from certain locations, or of certain categories, may be more commercially appealing than others, particularly classic metamorphic sapphires from Kashmir, Burma, or Sri Lanka that have not been subjected to heat-treatment. The Logan sapphire ,
5978-459: The center of the star near the top of the dome. Occasionally, twelve-rayed stars are found, typically because two different sets of inclusions are found within the same stone, such as a combination of fine needles of rutile with small platelets of hematite ; the first results in a whitish star and the second results in a golden-colored star. During crystallization, the two types of inclusions become preferentially oriented in different directions within
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#17328478007766076-409: The color penetration is far greater than with titanium diffusion. In some cases, it may penetrate the entire stone. Beryllium-diffused orange sapphires may be difficult to detect, requiring advanced chemical analysis by gemological labs ( e.g. , Gübelin, SSEF , GIA , American Gemological Laboratories (AGL), Lotus Gemology . According to United States Federal Trade Commission guidelines, disclosure
6174-470: The crystal, thereby forming two six-rayed stars that are superimposed upon each other to form a twelve-rayed star. Misshapen stars or 12-rayed stars may also form as a result of twinning . The inclusions can alternatively produce a cat's eye effect if the girdle plane of the cabochon is oriented parallel to the crystal's c-axis rather than perpendicular to it. To get a cat's eye, the planes of exsolved inclusions must be extremely uniform and tightly packed. If
6272-685: The deliberate addition of certain specific impurities (e.g. beryllium, titanium, iron, chromium or nickel, which are absorbed into the crystal structure of the sapphire) is also commonly performed, and this process can be known as "diffusion" in the gem trade. However, despite what the terms "heating only" and "diffusion" might suggest, both of these categories of treatment actually involve diffusion processes. The most complete description of corundum treatments extant can be found in Chapter 6 of Ruby & Sapphire: A Gemologist's Guide (chapter authored by John Emmett, Richard Hughes and Troy R. Douthit). In 1902,
6370-448: The dome is oriented in between these two directions, an off-center star will be visible, offset away from the high point of the dome. At 1404.49 carats, The Star of Adam is the largest known blue star sapphire. The gem was mined in the city of Ratnapura, southern Sri Lanka. The Black Star of Queensland , the second largest star sapphire in the world, weighs 733 carats . The Star of India mined in Sri Lanka and weighing 563.4 carats
6468-696: The entrance of emergency rescuers. Vehicles, such as buses, aircraft, and trains frequently have emergency exit windows as well. A stained glass window is a window composed of pieces of colored glass, transparent, translucent or opaque , frequently portraying persons or scenes. Typically the glass in these windows is separated by lead glazing bars. Stained glass windows were popular in Victorian houses and some Wrightian houses, and are especially common in churches . A French door has two rows of upright rectangular glass panes (lights) extending its full length; and two of these doors on an exterior wall and without
6566-451: The fixed pane. A tilt and turn window can both tilt inwards at the top or open inwards from hinges at the side. This is the most common type of window in Germany, its country of origin. It is also widespread in many other European countries. In Europe, it is usual for these to be of the "turn first" type. i.e. when the handle is turned to 90 degrees the window opens in the side hung mode. With
6664-537: The flaws that are found in natural stones. The disadvantage of the Verneuil process is that the grown crystals have high internal strains. Many methods of manufacturing sapphire today are variations of the Czochralski process , which was invented in 1916 by Polish chemist Jan Czochralski . In this process, a tiny sapphire seed crystal is dipped into a crucible made of the precious metal iridium or molybdenum , containing molten alumina, and then slowly withdrawn upward at
6762-497: The following terms: The European harmonised standard hEN 14351–1, which deals with doors and windows, defines 23 characteristics (divided into essential and non essential ). Two other, preliminary European Norms that are under development deal with internal pedestrian doors (prEN 14351–2), smoke and fire resisting doors, and openable windows (prEN 16034). Windows can be a significant source of heat transfer. Therefore, insulated glazing units consist of two or more panes to reduce
6860-545: The handle turned to 180 degrees the window opens in bottom hung mode. Most usually in the UK the windows will be "tilt first" i.e. bottom hung at 90 degrees for ventilation and side hung at 180 degrees for cleaning the outer face of the glass from inside the building. A transom window is a window above a door. In an exterior door the transom window is often fixed, in an interior door, it can open either by hinges at top or bottom, or rotate on hinges. It provided ventilation before forced air heating and cooling. A fan-shaped transom
6958-436: The highest premium, although Burma, Sri Lanka, and Madagascar also produce large quantities of fine quality gems. The cost of natural sapphires varies depending on their color, clarity, size, cut , and overall quality. Sapphires that are completely untreated are worth far more than those that have been treated. Geographical origin also has a major impact on price. For most gems of one carat or more, an independent report from
7056-521: The historic unavailability of large panes of glass, the multi-lit (or lattice window ) was the most common window style until the beginning of the 20th century, and is still used in traditional architecture. An emergency exit window is a window big enough and low enough so that occupants can escape through the opening in an emergency, such as a fire. In many countries, exact specifications for emergency windows in bedrooms are given in many building codes . Specifications for such windows may also allow for
7154-436: The industrial plate glass-making processes were perfected in the late 19th century Modern windows are usually filled using glass, although transparent plastic is also used. The introduction of lancet windows into Western European church architecture from the 12th century CE built on a tradition of arched windows inserted between columns, and led not only to tracery and elaborate stained-glass windows but also to
7252-462: The inside, resembling a hopper chute. A pivot window is a window hung on one hinge on each of two opposite sides which allows the window to revolve when opened. The hinges may be mounted top and bottom (Vertically Pivoted) or at each jamb (Horizontally Pivoted). The window will usually open initially to a restricted position for ventilation and, once released, fully reverse and lock again for safe cleaning from inside. Modern pivot hinges incorporate
7350-666: The largest faceted gem-quality blue sapphires in existence. Particolored sapphires (or bi-color sapphires) are those stones that exhibit two or more colors within a single stone. The desirability of particolored or bi-color sapphires is usually judged based on the zoning or location of their colors, the colors' saturation, and the contrast of their colors. Australia is the largest source of particolored sapphires; they are not commonly used in mainstream jewelry and remain relatively unknown. Particolored sapphires cannot be created synthetically and only occur naturally. Pink sapphires occur in shades from light to dark pink, and deepen in color as
7448-411: The latter term is a misnomer: synthetic color-change sapphires are, technically, not synthetic alexandrites but rather alexandrite simulants . This is because genuine alexandrite is a variety of chrysoberyl : not sapphire, but an entirely different mineral from corundum. Large rubies and sapphires of poor transparency are frequently used with suspect appraisals that vastly overstate their value. This
7546-675: The locale. Commonly, natural sapphires are cut and polished into gemstones and worn in jewelry . They also may be created synthetically in laboratories for industrial or decorative purposes in large crystal boules . Because of the remarkable hardness of sapphires – 9 on the Mohs scale (the third-hardest mineral, after diamond at 10 and moissanite at 9.5) – sapphires are also used in some non-ornamental applications, such as infrared optical components, high-durability windows , wristwatch crystals and movement bearings, and very thin electronic wafers , which are used as
7644-406: The most common secondary hues found in blue sapphires. The highest prices are paid for gems that are pure blue and of vivid saturation. Gems that are of lower saturation, or are too dark or too light in tone are of less value. However, color preferences are a personal taste. The 423-carat (84.6 g) Logan sapphire in the National Museum of Natural History , in Washington, D.C. , is one of
7742-434: The myriad criteria for the design of windows, several pivotal criteria have emerged in daylight standards: location, time, weather, nature, and people. Of these criteria, windows that are designed to provide views of nature are considered to be the most important by people. A cross-window is a rectangular window usually divided into four lights by a mullion and transom that form a Latin cross . The term eyebrow window
7840-631: The quantity of chromium increases. The deeper the pink color, the higher their monetary value . In the United States, a minimum color saturation must be met to be called a ruby , otherwise the stone is referred to as a pink sapphire . Padparadscha is a delicate, light to medium toned, pink-orange to orange-pink hued corundum , originally found in Sri Lanka , but also found in deposits in Vietnam and parts of East Africa . Padparadscha sapphires are rare;
7938-517: The rarest of all is the totally natural variety, with no sign of artificial treatment. The name is derived from the Sanskrit padma ranga (padma = lotus; ranga = color), a color akin to the lotus flower ( Nelumbo nucifera ). Among the fancy (non-blue) sapphires, natural padparadscha fetch the highest prices. Since 2001, more sapphires of this color have appeared on the market as a result of artificial lattice diffusion of beryllium. A star sapphire
8036-458: The same geographical settings, but they generally have different geological formations. For example, both ruby and sapphire are found in Myanmar's Mogok Stone Tract, but the rubies form in marble, while the sapphire forms in granitic pegmatites or corundum syenites. Every sapphire mine produces a wide range of quality, and origin is not a guarantee of quality. For sapphire, Jammu and Kashmir receives
8134-423: The sash. In the US, these are usually opened using a crank , but in parts of Europe, they tend to use projection friction stays and espagnolette locking. Formerly, plain hinges were used with a casement stay . Handing applies to casement windows to determine direction of swing; a casement window may be left-handed, right-handed, or double. The casement window is the dominant type now found in modern buildings in
8232-440: The stone could be worn as a pendant. On the back is a miniature plaque engraved with a short history of the Imperial State Crown. Sapphire Sapphire is a precious gemstone , a variety of the mineral corundum , consisting of aluminium oxide ( α- Al 2 O 3 ) with trace amounts of elements such as iron , titanium , cobalt , lead , chromium , vanadium , magnesium , boron , and silicon . The name sapphire
8330-412: The transfer of an electron from one transition-metal ion to another via the conduction or valence band . The iron can take the form Fe or Fe , while titanium generally takes the form Ti . If Fe and Ti ions are substituted for Al , localized areas of charge imbalance are created. An electron transfer from Fe and Ti can cause a change in the valence state of both. Because of the valence change, there
8428-506: The value of a sapphire, and most corundum of Kashmir origin can be readily identified by its characteristic silky appearance and exceptional hue. The unique blue appears lustrous under any kind of light, unlike non-Kashmir sapphires which may appear purplish or grayish in comparison. Sotheby's has been in the forefront overseeing record-breaking sales of Kashmir sapphires worldwide. In October 2014, Sotheby's Hong Kong achieved consecutive per-carat price records for Kashmir sapphires – first with
8526-445: The visible spectrum. This is an absorption band in the yellow (~590 nm), along with valleys of transmission in the blue-green and red. Thus the color one sees depends on the spectral composition of the light source. Daylight is relatively balanced in its spectral power distribution (SPD) and since the human eye is most sensitive to green light, the balance is tipped to the green side. However incandescent light (including candle light)
8624-416: The wall and does not extend to the ground. Originally a form of porch, they are often supported by brackets or corbels. Thermal, or Diocletian , windows are large semicircular windows (or niches) which are usually divided into three lights (window compartments) by two mullions. The central compartment is often wider than the two side lights on either side of it. A picture window is a large fixed window in
8722-426: The window be locked into hinges on one side, while the rope on the other side is detached—so the window can be opened for fire escape or cleaning. A foldup has two equal sashes similar to a standard double-hung but folds upward allowing air to pass through nearly the full-frame opening. The window is balanced using either springs or counterbalances, similar to a double-hung. The sashes can be either offset to simulate
8820-433: The window is opened. Windows are primarily designed to facilitate a vital connection with the outdoors, offering those within the confines of the building visual access to the everchanging events occurring outside. The provision of this connection serves as an integral safeguard for the health and well-being of those inhabiting buildings, lest they experience the detrimental effects of enclosed buildings devoid of windows. Among
8918-404: The window were used. These were and are attached to the sashes using pulleys of either braided cord or, later, purpose-made chain. Three types of spring balances are called a tape or clock spring balance; channel or block-and-tackle balance, and a spiral or tube balance. Double-hung sash windows were traditionally often fitted with shutters . Sash windows can be fitted with simplex hinges that let
9016-399: The windows of ordinary homes only in the early 17th century whereas windows made up of panes of flattened animal horn were used as early as the 14th century. In the 19th century American west, greased paper windows came to be used by pioneering settlers. Modern-style floor-to-ceiling windows became possible only after the industrial plate glass making processes were fully perfected. In
9114-507: The world's production of synthetic sapphire was 250 tons (1.25 × 10 carats), mostly by the United States and Russia. The availability of cheap synthetic sapphire unlocked many industrial uses for this unique material. Window A window is an opening in a wall , door , roof , or vehicle that allows the exchange of light and may also allow the passage of sound and sometimes air . Modern windows are usually glazed or covered in some other transparent or translucent material ,
9212-416: The year 2000, beryllium diffused "padparadscha" colored sapphires entered the market. Typically beryllium is diffused into a sapphire under very high heat, just below the melting point of the sapphire. Initially ( c. 2000 ) orange sapphires were created, although now the process has been advanced and many colors of sapphire are often treated with beryllium. Due to the small size of the beryllium ion,
9310-490: Was named " Serendipity Sapphire ". A rare variety of natural sapphire, known as color-change sapphire, exhibits different colors in different light. Color change sapphires are blue in outdoor light and purple under incandescent indoor light, or green to gray-green in daylight and pink to reddish-violet in incandescent light. Color-change sapphires come from a variety of locations, including Madagascar , Myanmar , Sri Lanka and Tanzania . Two types exist. The first features
9408-540: Was not commonly disclosed; by the late 1980s, heat treatment became a major issue. At that time, much of all the world's sapphires were being heated to enhance their natural color. Intergem's marketing of guaranteed untreated Yogos set them against many in the gem industry. This issue appeared as a front-page story in The Wall Street Journal on 29 August 1984 in an article by Bill Richards, Carats and Schticks: Sapphire Marketer Upsets The Gem Industry . However,
9506-601: Was practically abandoned just a few years later because of the difficulties in recovering sapphires in their bedrock. In North America , sapphires have been mined mostly from deposits in Montana : facies along the Missouri River near Helena, Montana , Dry Cottonwood Creek near Deer Lodge, Montana , and Rock Creek near Philipsburg, Montana . Fine blue Yogo sapphires are found at Yogo Gulch west of Lewistown, Montana . A few gem-grade sapphires and rubies have also been found in
9604-668: Was the case of the "Life and Pride of America Star Sapphire". Circa 1985, Roy Whetstine claimed to have bought the 1905-ct stone for $ 10 at the Tucson gem show, but a reporter discovered that L.A. Ward of Fallbrook, California, who appraised it at the price of $ 1200/ct, had appraised another stone of the exact same weight several years before Whetstine claimed to have found it. Bangkok-based Lotus Gemology maintains an updated listing of world auction records of ruby, sapphire, and spinel . As of November 2019, no sapphire has ever sold at auction for more than $ 17,295,796. Rubies are corundum with
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