"color as 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; the rarest of all is the totally natural variety, with no sign of artificial treatment. The name is derived from the Sanskrit ""padma"
"Golden sheen sapphire Golden Sheen Sapphire, is a gemstone variety of the mineral corundum, an aluminium oxide (). It typically shows a metallic golden colour with common variations being brass, copper and bronze, however metallic blue, green and yellow colouration is also possible. A very rare variation is a metallic red colour. Unlike normal sapphire, golden sheen sapphire occurs principally as a result of iron and titanium inclusions, making the gem mostly opaque. In this respect, golden sheen sapphire is more like opal than other typically clear or transparent gemstone. Identified inclusions in golden sheen sapphire are ilmenite, rutile, hematite"
"only in ruby. Sapphire and ruby are both varieties of the same mineral; corundum. Some minerals may replace other existing minerals while preserving the original's habit: this process is called pseudomorphous replacement. A classic example is tiger's eye quartz, crocidolite asbestos replaced by silica. While quartz typically forms ""prismatic"" (elongate, prism-like) crystals, in tiger's eye the original ""fibrous"" habit of crocidolite is preserved. The names of crystal habits are derived from: Predominant crystal faces (prism – prismatic, pyramid – pyramidal and pinacoid – platy). Crystal forms (cubic, octahedral, dodecahedral). Aggregation of crystals or aggregates (fibrous, botryoidal, radiating, massive). Crystal appearance"
"have the same primary chemical composition (both are corundum) but exhibit different colors because of impurities. Even the same named gemstone can occur in many different colors: sapphires show different shades of blue and pink and ""fancy sapphires"" exhibit a whole range of other colors from yellow to orange-pink, the latter called ""padparadscha sapphire"". This difference in color is based on the atomic structure of the stone. Although the different stones formally have the same chemical composition and structure, they are not exactly the same. Every now and then an atom is replaced by a completely different atom, sometimes as"
"for golden sheen sapphire. Testing of heat treatment on sample batches has resulted in diminishment of the gold sheen effect, reducing the appeal of the gemstone. The name 'golden sheen sapphire' is often shortened to 'gold sheen sapphire' and the name is interchangeable. Golden sheen sapphire has been used in jewelry production by companies including In 2016 a gold sheen sapphire ring by William Travis Jewelry won the American Gem Trade Association Savor Silver Award, Men's Wear. Golden sheen sapphire Golden Sheen Sapphire, is a gemstone variety of the mineral corundum, an aluminium oxide (). It typically shows a metallic"
"actually corundum laced with trace elements (e.g., vanadium) or color-change spinel and are not actually chrysoberyl. As a result, they would be more accurately described as ""simulated alexandrite"" rather than “synthetic”. This alexandrite-like sapphire material has been around for almost 100 years and shows a characteristic purple-mauve colour change, which does not really look like alexandrite because there is never any green. Translucent yellowish chatoyant chrysoberyl is called cymophane or ""cat's eye"". Cymophane has its derivation also from the Greek words meaning 'wave' and 'appearance', in reference to the haziness that visually distorts what would normally be viewed as a"
"of Yogo sapphires claim that ""yogo"" may mean ""romance"" or ""blue sky"" in the Blackfoot language, although there is little evidence to support this claim. Other meanings for ""yogo"" have been suggested, including ""Going over the hill"". The meaning of the word ""Yogo"" had been lost by 1878, when placer gold was found in Yogo Creek. Thus, its true meaning is uncertain. Sapphires are a color variety of corundum, a crystalline form of aluminium oxide (). Corundum is one of the hardest minerals, rating 9 on the Mohs scale. Corundum gems of most colors are called sapphires, except for red"
"to yellow sapphire after oxidizing. After heating geuda to roughly 1800 °C, the aluminium oxide lattice-work of the gem is disrupted and cooling greatly improves both color and clarity. Though many stones are destroyed by the heating and cooling process, those that survive are significantly altered and rival naturally blue sapphires in both appearance and price. Geuda Geuda (, pronounced gay-yoo-dah) is a form of the mineral corundum, or sapphire, found primarily in Sri Lanka. Around 70%-80% of gems mined in Sri Lanka belong to geuda varieties. Because of its semitransparent and milky appearance due to rutile inclusions, these stones"
"10.0 and moissanite falling somewhere in between corundum (ruby) and diamond in hardness. Sapphire, ruby, and pure corundum are α-alumina, the most stable form of AlO, in which 3 electrons leave each aluminum ion to join the regular octahedral group of six nearby O ions; in pure corundum this leaves all of the aluminum ions with a very stable configuration of no unpaired electrons or unfilled energy levels, and the crystal is perfectly colorless. When a chromium atom replaces an occasional aluminum atom, it too loses 3 electrons to become a chromium ion to maintain the charge balance of the"
"formula units. The toughness of corundum is sensitive to surface roughness and crystallographic orientation. It may be 6-7 MPa·m for synthetic crystals, and ~4 for natural In the lattice of corundum, the oxygen atoms form a slightly distorted hexagonal close packing, in which two-thirds of the gaps between the octahedra are occupied by aluminum ions. Corundum Corundum is a crystalline form of aluminium oxide () typically containing traces of iron, titanium, vanadium and chromium. It is a rock-forming mineral. It is also a naturally transparent material, but can have different colors depending on the presence of transition metal impurities in"
"Emery (rock) Emery (or corundite) is a dark granular rock used to make abrasive powder. It largely consists of the mineral corundum (aluminium oxide), mixed with other species such as the iron-bearing spinels, hercynite, and magnetite, and also rutile (titania). Industrial emery may contain a variety of other minerals and synthetic compounds such as magnesia, mullite, and silica. It is black or dark grey in colour, less dense than translucent-brown corundum with a specific gravity of between 3.5 and 3.8. Because it can be a mixture of minerals, no definite Mohs hardness can be assigned: the hardness of corundum is"
"sleepy quality, described by some gem enthusiasts as ‘blue velvet”. Kashmir-origin contributes meaningfully to 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 the 12.00 carat Cartier sapphire ring at US$193,975 per carat, then with"
"Geuda Geuda (, pronounced gay-yoo-dah) is a form of the mineral corundum, or sapphire, found primarily in Sri Lanka. Around 70%-80% of gems mined in Sri Lanka belong to geuda varieties. Because of its semitransparent and milky appearance due to rutile inclusions, these stones have little value as gemstones in their natural state. Geuda was frequently stored in large drums or used to gravel home gardens prior to the 1970s discovery that heat treatment can drastically alter the stone's color. Some geuda varieties turn to a blue color after heat treatments. Others turn to red after oxidizing. Kowangu pushparaga turns"
"the temple is a model and reminder of this cosmic homology. The Garuda Purana describes 14 gems, their varieties and how to test their quality. The gems discussed include Ruby, Pearl, Yellow Sapphire, Hessonite, Emerald, Diamond, Cats eye, Blue Sapphire, Coral, Red Garnet, Jade, colorless Quartz, and Bloodstone. The technical discussion of gems in the text is woven with its theories on the mythical creation of each gem, astrological significance and talisman benefits. The text describes the characteristics of the gems, how to clean and make jewelry from them, cautioning that gem experts should be consulted before buying them. For"
"Yogo sapphire Yogo sapphires are a variety of corundum found only in Yogo Gulch, part of the Little Belt Mountains in Judith Basin County, Montana, United States, on land once inhabited by the Piegan Blackfeet people. Yogos are typically cornflower blue, a result of trace amounts of iron and titanium. They have high uniform clarity and maintain their brilliance under artificial light. Because Yogo sapphires occur within a vertically dipping resistive igneous dike, mining efforts have been sporadic and rarely profitable. It is estimated that at least 28 million carats () of Yogos are still in the ground. Jewelry containing"
"Ruby and Corundum var: Sapphire.(Ref: E.Ya. Kievlenko, Geology of gems, 2003, p. 55). In early '70s there was a special project of mining (gem stones) which wasat a standstill due to government action. Nowadays some young people mainly unemployed try to find some ruby and other precious gems in long tunnels approximately 1 km long. The town management society of Dourkhan is working on development and infrastructure improvement with the support of AKDN and other international NGOs. Recently a sewage-system project was completed, and a safe-drinking-water project is near its completion. Dourkhan Dourkhan a small town in Gilgit–Baltistan, Pakistan, 1"
"in turn derives from the Sanskrit ""Kuruvinda"". Because of corundum's hardness (pure corundum is defined to have 9.0 on the Mohs scale), it can scratch almost every other mineral. It is commonly used as an abrasive on everything from sandpaper to large tools used in machining metals, plastics, and wood. Some emery is a mix of corundum and other substances, and the mix is less abrasive, with an average Mohs hardness of 8.0. In addition to its hardness, corundum has a density of , which is unusually high for a transparent mineral composed of the low-atomic mass elements aluminium and"
"golden sheen sapphire as corundum, describing the gold sheen effect as 'known in the industry as gold sheen sapphire', include: Golden sheen sapphire is only known to come from one source, an undisclosed mine in the north east of Kenya near the Somali border. Gem-A note “To our knowledge, no corrundum deposits have been reported in areas near Somalia.” (Page 689, Journal of Gemmology) Golden Sheen Sapphire will exhibit mild to strong color change under warm, cool and direct sunlight. All cabochon cut Golden Sheen Sapphire will exhibit some degree of asterism. There are no known heating or treatment methods"
"produce aluminium metal, as an abrasive owing to its hardness, and as a refractory material owing to its high melting point. Corundum is the most common naturally occurring crystalline form of aluminium oxide. Rubies and sapphires are gem-quality forms of corundum, which owe their characteristic colors to trace impurities. Rubies are given their characteristic deep red color and their laser qualities by traces of chromium. Sapphires come in different colors given by various other impurities, such as iron and titanium. AlO is an electrical insulator but has a relatively high thermal conductivity () for a ceramic material. Aluminium oxide is"
"oxygen. Corundum occurs as a mineral in mica schist, gneiss, and some marbles in metamorphic terranes. It also occurs in low silica igneous syenite and nepheline syenite intrusives. Other occurrences are as masses adjacent to ultramafic intrusives, associated with lamprophyre dikes and as large crystals in pegmatites. It commonly occurs as a detrital mineral in stream and beach sands because of its hardness and resistance to weathering. The largest documented single crystal of corundum measured about , and weighed . The record has since been surpassed by certain synthetic boules. Corundum for abrasives is mined in Zimbabwe, Pakistan, Afghanistan, Russia,"
"Purple sapphires contain trace amounts of vanadium and come in a variety of shades. Corundum that contains ~0.01% of titanium is colorless. 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 deep-blue color. 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 the transfer of an electron from one transition-metal ion to another via the conduction"
"purple-mauve color change which, although attractive, differs from alexandrite because there is never any green. The stones will be very clean and may be available in large sizes. Gemological testing will reveal a refractive index of 1.759–1.778 (corundum) instead of 1.741–1.760 (chrysoberyl). Under magnification, gas bubbles and curved stria may be evident. When examined with a spectroscope a strong vanadium absorption line at 475 nm will be apparent. Synthetic alexandrite Synthetic alexandrite is an artificially-grown variety of chrysoberyl crystal, composed of beryllium aluminum oxide (BeAlO). The name is also often used erroneously to describe synthetically-grown corundum. Most true synthetic Alexandrite"
"Associated minerals include augite, hornblende, diopside, grossular, biotite, phlogopite, monticellite, wollastonite, calcite, spinel, magnetite and perovskite. Cuspidine Cuspidine is a fluorine bearing calcium silicate mineral (sorosilicate) with formula: Ca(SiO)(F,OH). Cuspidine crystallizes in the monoclinic crystal system and occurs as acicular to spear shaped pale red to light brown crystals. It is a member of the wöhlerite group. Cuspidine was first described in 1876 for an occurrence in Monte Somma, Italy. The name is from the Greek ""cuspis"" for ""spear"" from its characteristic crystal form. Cuspidine occurs as crystals in tuff from Monte Somma. In the Franklin, New Jersey mine area"
"stone. Chatoyant minerals display luminous bands, which appear to move as the specimen is rotated. Such minerals are composed of parallel fibers (or contain fibrous voids or inclusions), which reflect light into a direction perpendicular to their orientation, thus forming narrow bands of light. The most famous examples are tiger's eye and cymophane, but the effect may also occur in other minerals such as aquamarine, moonstone and tourmaline. Color change is most commonly found in alexandrite, a variety of chrysoberyl gemstones. Other gems also occur in color-change varieties, including (but not limited to) sapphire, garnet, spinel. Alexandrite displays a color"
"smaller white diamonds. As with all star sapphires the star moves with changing angles of illumination and observation and belongs to the group of minerals known as corundum, a crystalline form of aluminum oxide (AlO). The star effect in star sapphires is caused by microscopic inclusions, mainly Rutile, aligned in a threefold pattern inside the stone that reflects the light entering the stone through its dome shaped face into a six-rayed star pattern. In 1947, Harry Spencer agreed to sell the stone to Armenian-born jeweler Harry Kazanjian for $18,000, with which Spencer built a new house for his family. Harry"
"In late classical times and as late as the Middle Ages, lapis lazuli was often called sapphire (""sapphirus"" in Latin, ""sappir"" in Hebrew), though it had little to do with the stone today known as the blue corundum variety sapphire. In his book on stones, the Greek scientist Theophrastus described ""the sapphirus, which is speckled with gold,"" a description which matches lapis lazuli. There are many references to sapphires in the Old Testament, but most scholars agree that, since sapphire was not known before the Roman Empire, they most likely are references to lapis lazuli. For instance, Exodus 24:10: ""And"
"along strike and to depth. On 17 May 2011 an initial resource calculation was announced for Aappaluttoq. The resource included indicated resources of 189,150 tonnes of material hosting 59 million grams (296 million carats) of corundum and inferred a further 21 million grams (109 million carats) of material was present at Aappaluttoq to a depth of 65m. The deposit remains open along strike and to depth. The resource is National Instrument 43-101 compliant and is the first coloured gemstone resource ever to be published under these laws. True North Gems has initiated a socio-economic impact assessment in anticipation of a"
"varieties tend to be macrocrystalline. Chalcedony is a cryptocrystalline form of silica consisting of fine intergrowths of both quartz, and its monoclinic polymorph moganite. Other opaque gemstone varieties of quartz, or mixed rocks including quartz, often including contrasting bands or patterns of color, are agate, carnelian or sard, onyx, heliotrope, and jasper. Amethyst is a form of quartz that ranges from a bright to dark or dull purple color. The world's largest deposits of amethysts can be found in Brazil, Mexico, Uruguay, Russia, France, Namibia and Morocco. Sometimes amethyst and citrine are found growing in the same crystal. It is"
"Dome Rock Mountains of La Paz County, Arizona, Stockdale, Riley County, Kansas; Cortlandt, New York; and Clay County, North Carolina. Sapphirine Sapphirine is a rare mineral, a silicate of magnesium and aluminium with the chemical formula (Mg,Al)(Al,Si)O (with iron as a major impurity). Named for its sapphire-like colour, sapphirine is primarily of interest to researchers and collectors: well-formed crystals are treasured and occasionally cut into gemstones. Sapphirine has also been synthesized for experimental purposes via a hydrothermal process. Typical colours range from light to dark sapphire blue, bluish to brownish green, green, and bluish or greenish gray to black; less"
"or yellow gold and a dual time version in either yellow or white gold. The Corum Golden Bridge collection is unique in the watchmaking world. Its four sapphire sides offer an unrestricted view of the intricately detailed linear movement, which appears to be floating in mid-air, held only by the gold bridge that names this watch. The Corum Golden Bridge is offered in 18k gold or platinum, and is also available with delicate diamond work. The Corum Tourbillon and Classical collection comprise the Corum Classical Billionaire Tourbillon, a diamond and sapphire-covered masterpiece of watchmaking, the Corum Golden Tourbillon Panoramique with"
"of a revolutionary process of horizontal crystallization for growing corundum (ruby), chrysoberyl and alexandrite. After many years of development, scientists at Tairus had succeeded to commercially grow emeralds in a laboratory environment that resemble in color and have gemological properties that “overlap natural emeralds from various localities, especially those of low alkali-bearing stones from Colombia” (The Journal of Gemmology, 2006, Vol. 30, Nos 1/2, 59-74). The following are synthetic gemstones that were developed by Tairus scientists; they are alternately referred to as Tairus stones (e.g. ""Tairus Ruby""). Tairus Tairus (, a portmanteau of Тайско (Thai) and Русский (Russian)) is a"
"a supplement for the prevention and treatment of osteoporosis and arthritis. Carbon is the chemical element with atomic number 6, occurring as C, C and C. At standard temperature and pressure, carbon is a solid, occurring in many different allotropes, the most common of which are graphite, diamond, the fullerenes and amorphous carbon. Graphite is a soft, hexagonal crystalline, opaque black semimetal with very good conductive and thermodynamically stable properties. Diamond however is a highly transparent colourless cubic crystal with poor conductive properties, is the hardest known naturally occurring mineral and has the highest refractive index of all gemstones. In"
"Star of Bombay The Star of Bombay is a 182-carat (36.4-g) cabochon-cut star sapphire originating from Sri Lanka. The violet-blue gem was given to silent film actress Mary Pickford by her husband, Douglas Fairbanks. She bequeathed it to the Smithsonian Institution. It is the namesake of the popular alcoholic beverage Bombay Sapphire, a British-manufactured gin. The ""Star of Bombay"" is a 182 carat (36.4-g) cabochon-cut star sapphire. According to Southern Jewelry News, ""The Star of Bombay sapphire belongs to the mineral species corundum. Pure corundum is colorless, but trace amounts of transition elements like vanadium or chromium result in different"