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Chatoyant
In gemology, chatoyancy ( ), also called chatoyance or the cat's eye effect, is an optical reflectance effect seen in certain gemstones. (Historically, the term has applied specifically to gems; in woods and other materials the effect is more broadly known as "figure" or iridescence.) Coined from the French , meaning cat's eye, the chatoyant effect is typically characterized by one or more well-defined bands of reflected light, reminiscent of a cat's eye, which appear to glide across a gem's surface as the object is moved, or when the observer moves while viewing it. Chatoyancy is caused by the presence of fibrous structures within the material, such as in tiger's eye quartz, or by fibrous inclusions and cavities, as seen in cat's eye chrysoberyl, in which the effect is caused by the presence of titanium dioxide, which aligns perpendicularly to produce the effect. Description Chatoyancy in the gemstone chrysoberyl is induced by the presence of the mineral rutile, a mineral ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tigers-Eye
Tiger's eye (also called tiger eye) is a chatoyant gemstone that is usually a metamorphic rock with a golden to red-brown colour and a silky lustre. As members of the quartz group, tiger's eye and the related blue-coloured mineral hawk's eye gain their silky, lustrous appearance from the parallel intergrowth of quartz crystals and altered amphibole fibres that have mostly turned into limonite. Other forms of tiger's eye ''Tiger iron'' is an altered rock composed chiefly of tiger's eye, red jasper and black hematite. The undulating, contrasting bands of colour and lustre make for an attractive motif and it is mainly used for jewellery-making and ornamentation. Tiger iron is a popular ornamental material used in a variety of applications, from beads to knife hilts. Tiger iron is mined primarily in South Africa and Western Australia. Tiger's eye is composed chiefly of silicon dioxide () and is coloured mainly by iron oxide. The specific gravity ranges from 2.64 to 2.71. It is f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charoite
Charoite ( ) is a rare silicate mineral with the chemical composition , first described in 1978. It is named after the Chara River, despite its being away from the discovery place.Ian Frazier, ''Travels in Siberia'', Farrar, Straus and Giroux, New York (NY), 2010, ISBN 978-0-374-27872-4page 394/ref> When it was discovered, it was thought to be a fake, dyed purple to give it its striking appearance. Properties Charoite is translucent lavender to purple in color with a pearly luster. Charoite is strictly massive in nature, and fractures are conchoidal. It has an unusual swirling, fibrous appearance, sometimes chatoyant, and that, along with its intense color, can lead many to believe at first that it is synthetic or enhanced artificially. Though reportedly discovered in the 1940s, it was not known to most of the world until its description in 1978. It is said to be opaque and unattractive when found in the field; a fact that may have contributed to its late recognition. Charoi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tiger's Eye
Tiger's eye (also called tiger eye) is a chatoyant gemstone that is usually a metamorphic rock with a golden to red-brown colour and a silky lustre. As members of the quartz group, tiger's eye and the related blue-coloured mineral hawk's eye gain their silky, lustrous appearance from the parallel intergrowth of quartz crystals and altered amphibole fibres that have mostly turned into limonite. Other forms of tiger's eye ''Tiger iron'' is an altered rock composed chiefly of tiger's eye, red jasper and black hematite. The undulating, contrasting bands of colour and lustre make for an attractive motif and it is mainly used for jewellery-making and ornamentation. Tiger iron is a popular ornamental material used in a variety of applications, from beads to knife hilts. Tiger iron is mined primarily in South Africa and Western Australia. Tiger's eye is composed chiefly of silicon dioxide () and is coloured mainly by iron oxide. The specific gravity ranges from 2.64 to 2.71. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chrysoberyl
The mineral or gemstone chrysoberyl is an aluminate of beryllium with the formula Be Al2 O4. The name chrysoberyl is derived from the Greek words χρυσός ''chrysos'' and βήρυλλος ''beryllos'', meaning "a gold-white spar". Despite the similarity of their names, chrysoberyl and beryl are two completely different gemstones, although they both contain beryllium. Chrysoberyl is the third-hardest frequently encountered natural gemstone and lies at 8.5 on the Mohs scale of mineral hardness, between corundum (9) and topaz (8). An interesting feature of its crystals are the cyclic twins called ''trillings''. These twinned crystals have a hexagonal appearance, but are the result of a triplet of twins with each "twin" oriented at 120° to its neighbors and taking up 120° of the cyclic trilling. If only two of the three possible twin orientations are present, a V-shaped twin results. Ordinary chrysoberyl is yellowish-green and transparent to translucent. When the min ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cabochon
A cabochon (; ) is a gemstone that has been shaped and polished, as opposed to faceted. The resulting form is usually a convex (rounded) obverse with a flat reverse. Cabochon was the default method of preparing gemstones before gemstone cutting developed. Application Cutting ''en cabochon'' (French: "in the manner of a cabochon") is usually applied to opaque gems, while faceting is usually used for transparent stones. Hardness is also taken into account as softer gemstones with a hardness lower than 7 on the Mohs hardness scale are easily scratched, mainly by silicon dioxide in dust and grit. This would quickly make translucent gems unattractive—instead they are polished as cabochons, making the scratches less evident. In asteriated stones such as star sapphires and chatoyant stones such as cat's eye chrysoberyl, a domed cabochon cut can show the star or eye, which would not be visible in a faceted cut. The usual shape for cutting cabochons is an ellipse, because the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apatite
Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of Hydroxide, OH−, Fluoride, F− and Chloride, Cl− ion, respectively, in the crystal. The formula of the admixture of the three most common Endmember (mineralogy), endmembers is written as Calcium, Ca10(Phosphate, PO4)6(OH,F,Cl)2, and the crystal unit cell formulae of the individual minerals are written as Ca10(PO4)6(OH)2, Ca10(PO4)6F2 and Ca10(PO4)6Cl2. The mineral was named apatite by the German geologist Abraham Gottlob Werner in 1786, although the specific mineral he had described was reclassified as fluorapatite in 1860 by the German mineralogist Karl Friedrich August Rammelsberg. Apatite is often mistaken for other minerals. This tendency is reflected in the mineral's name, which is derived from the Greek word ἀπατάω (apatáō), which means ''to deceive''. Geology Apatite is very common as an accessory mineral in igneous and metamorphic roc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenite (mineral)
Selenite, satin spar, desert rose, and gypsum flower are crystal habit varieties of the mineral gypsum. All varieties of gypsum, including selenite and alabaster, are composed of calcium sulfate dihydrate (meaning that it has two molecules of water), with the chemical formula CaSO4·2H2O. Selenite contains no selenium; the similar names both derive from Greek ( 'Moon'). Some of the largest crystals ever found are of selenite, the largest specimen found in the Naica Mine's Cave of the Crystals being 12 meters long and weighing 12 tons. History and etymology "Selenite" is mostly synonymous with gypsum, but from the 15th century, it has named the transparent variety that occurs in crystals or crystalline masses. The name derives through Middle English from Latin , ultimately from Greek (, ). It got this name because people historically believed the mineral waxed and waned with the cycles of the Moon. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moonstone (gemstone)
Moonstone is a sodium potassium aluminium silicate minerals, silicate ((Na,K)AlSi3O8) of the feldspar group that displays a pearly and opalescence, opalescent Lustre (mineralogy)#Schiller, schiller. An alternative name for moonstone is hecatolite (from goddess Hecate). Etymology The name ''moonstone'' derives from the stone's characteristic visual effect, called adularescence (or schiller), which produces a milky, bluish interior light. This effect is caused by light diffraction through alternating layers of orthoclase and albite within the stone. The diffracted light varies from white to blue, depending on the thinness of the albite layers. More technically, this micro-structure consists of regular exsolution layers (lamellae) of different alkali feldspars (orthoclase and sodium-rich plagioclase). Polished moonstones often display chatoyancy ("cat's eye" effect), where a luminous streak appears through the stone. Asterism (gemology), Asterism is rare and produces four-legged ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomsonite
Thomsonite is the name of a series of tectosilicate minerals of the zeolite group. Prior to 1997, thomsonite was recognized as a mineral species, but a reclassification in 1997 by the International Mineralogical Association changed it to a series name, with the mineral species being named thomsonite-Ca and thomsonite-Sr. Thomsonite-Ca, by far the more common of the two, is a hydrous sodium, calcium and aluminium silicate, NaCa2Al5Si5O20·6H2O. Strontium can substitute for the calcium and the appropriate species name depends on the dominant element. The species are visually indistinguishable and the series name thomsonite is used whenever testing has not been performed. Globally, thomsonite is one of the rarer zeolites. Thomsonite was first identified in material from Scotland in 1820. It is named for the Scottish chemist Thomas Thomson. The crystal system of thomsonite is orthorhombic. The Mohs hardness is 5 to 5.5. It is transparent to translucent and has a density of 2. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scapolite
The scapolites (, "rod", and , "stone") are a group of rock-forming silicate minerals composed of aluminium, calcium, and sodium silicate with chlorine, carbonate and sulfate. The two endmembers are meionite () and marialite (). Silvialite is also a recognized member of the group. Properties The group is an isomorphous mixture of the meionite and marialite endmembers. The tetragonal crystals are hemihedral with parallel faces (like scheelite), and at times of considerable size. They are distinct and usually have the form of square columns, some cleavages parallel to the prism-faces. Crystals are usually white or greyish-white and opaque, though meionite is found as colorless glassy crystals in the ejected limestone blocks of Monte Somma, Vesuvius. The hardness is 5–6, and the specific gravity varies with the chemical composition between 2.7 (meionite) and 2.5 (marialite). The scapolites are especially liable to alteration by weathering processes, with the developmen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tigers Eye Chatometry
The tiger (''Panthera tigris'') is a large Felidae, cat and a member of the genus ''Panthera'' native to Asia. It has a powerful, muscular body with a large head and paws, a long tail and orange fur with black, mostly vertical stripes. It is traditionally classified into nine Holocene, recent subspecies, though some recognise only two subspecies, mainland Asian tigers and the island tigers of the Sunda Islands. Throughout the tiger's range, it inhabits mainly forests, from coniferous and temperate broadleaf and mixed forests in the Russian Far East and Northeast China to tropical and subtropical moist broadleaf forests on the Indian subcontinent and Southeast Asia. The tiger is an apex predator and preys mainly on ungulates, which it takes by ambush. It lives a mostly solitary life and occupies home ranges, defending these from individuals of the same sex. The range of a male tiger overlaps with that of multiple females with whom he mates. Females give birth to usually two or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Fiber
An optical fiber, or optical fibre, is a flexible glass or plastic fiber that can transmit light from one end to the other. Such fibers find wide usage in fiber-optic communications, where they permit transmission over longer distances and at higher Bandwidth (computing), bandwidths (data transfer rates) than electrical cables. Fibers are used instead of metal wires because signals travel along them with less Attenuation, loss and are immune to electromagnetic interference. Fibers are also used for illumination (lighting), illumination and imaging, and are often wrapped in bundles so they may be used to carry light into, or images out of confined spaces, as in the case of a fiberscope. Specially designed fibers are also used for a variety of other applications, such as fiber optic sensors and fiber lasers. Glass optical fibers are typically made by Drawing (manufacturing), drawing, while plastic fibers can be made either by drawing or by extrusion. Optical fibers typically incl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
