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Chatoyancy
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] |
Labradorite
Labradorite (( Ca, Na)( Al, Si)4 O8) is a calcium-enriched feldspar mineral first identified in Labrador, Canada, which can display an iridescent effect ( schiller). Labradorite is an intermediate to calcic member of the plagioclase series. It has an anorthite percentage (%An) of between 50 and 70. The specific gravity ranges from 2.68 to 2.72. The streak is white, like most silicates. The refractive index ranges from 1.559 to 1.573 and twinning is common. As with all plagioclase members, the crystal system is triclinic, and three directions of cleavage are present, two of which are nearly at right angles and are more obvious, being of good to perfect quality (while the third direction is poor). It occurs as clear, white to gray, blocky to lath shaped grains in common mafic igneous rocks such as basalt and gabbro, as well as in anorthosites. Occurrence The geological type area for labradorite is Paul's Island near the town of Nain in Labrador, Canada. It has also been rep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird's Eye Figure
Bird's eye is a type of figure that occurs within several kinds of wood, most notably hard maple. It has a distinctive pattern that resembles tiny, swirling eyes disrupting the smooth lines of grain. It is somewhat reminiscent of a burl, but it is quite different: the small knots that make the burl are missing. It is not known what causes the phenomenon. Research into the cultivation of bird's eye maple has so far discounted the theories that it is caused by pecking birds deforming the wood grain or that an infecting fungus makes it twist. However, no one has demonstrated a complete understanding of any combination of climate, soil, tree variety, insects, viruses, or genetic mutations that may produce the effect. Bird's eye maple is most often found in ''Acer saccharum'' (sugar maple), but millers also find bird's eye figures in red maple, white ash, Cuban mahogany, American beech, black walnut, and yellow birch. Trees that grow in the Great Lakes region of Canada and the U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burl
A burl (American English) or burr (British English) is a tree growth in which the grain has grown in a deformed manner. It is commonly found in the form of a rounded outgrowth on a tree trunk or branch that is filled with small knots from dormant buds. Burl formation is typically a result of some form of stress such as an injury or a viral or fungal infection. More scientifically, a burl is “the result of hyperplasia, a greatly abnormal proliferation of xylem production by the vascular cambium”. Burls yield a very peculiar and highly figured wood sought after in woodworking, and some items may reach high prices on the wood market. Poaching of burl specimens and damaging the trees in the process poses a problem in some areas. Description A burl results from a tree undergoing some form of stress. It may be caused by a virus, fungus or ''Agrobacterium tumefaciens'' entering the plant through an injury. Most burls grow beneath the ground, attached to the roots as a type ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanmu
Nanmu () is a precious wood that is unique to China and South Asia, and was historically used for boat building, architectural woodworking, furniture and sculptural carving in China. The Ming dynasty-era writings indicate this wood as superior durable softwood. A recent excavation of a tomb in Lija village in Jing'an County, Jiangxi Province, found 47 coffins made of nanmu wood that are reported to be about 2500 years old, dating back to the Eastern Zhou dynasty period and belonging to the Dongyi State of Xu. The trees that produce nanmu wood are evergreens that have long, straight trunks which grows to 35 meters in height and one meter in diameter. More than 30 varieties exist, which are found south of the Yangtze River. There are also nanmu trees on Hainan Island and in Vietnam. Yangmu nanmu is found in Sichuan. Zinan nanmu is found in southeast and south central China. Zinanmu nanmu is found in Jiangsu, Anhui, Zhenjiang. Zhennan nanmu is found in Guizhou and Sichuan. The fines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardwood
Hardwood is wood from Flowering plant, angiosperm trees. These are usually found in broad-leaved temperate and tropical forests. In temperate and boreal ecosystem, boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen. Hardwood (which comes from angiosperm trees) contrasts with softwood (which is from gymnosperm trees). Characteristics Hardwoods are produced by Flowering plant, angiosperm trees that reproduce by flowers, and have broad leaves. Many species are deciduous. Those of temperate regions lose their leaves every autumn as temperatures fall and are dormant in the winter, but those of tropical regions may shed their leaves in response to seasonal or sporadic periods of drought. Hardwood from deciduous species, such as oak, normally shows annual dendrochronology, growth rings, but these may be absent in some tropical timber, tropical hardwoods. Hardwoods have a more complex structure than softwoods and are often much slower growing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquamarine (gemstone)
Aquamarine is a pale-blue to light-green variety of the beryl, beryl family, with its name relating to water and sea. The color of aquamarine can be changed by heat, with a goal to enhance its physical appearance (though this practice is frowned upon by collectors and jewelers). It is the birth stone of March. Aquamarine is a fairly common gemstone, rendering it more accessible for purchase, compared to other gems in the beryl family. Overall, its value is determined by weight, color, cut, and clarity. It is transparent to translucent and possesses a hexagonal crystal system. Aquamarine mainly forms in granite pegmatites and hydrothermal veins, and it is a very lengthy process that can take millions of years to form. Aquamarine occurs in many countries over the world, and is most commonly used for jewelry, decoration and its properties. Aquamarine is mainly extracted through open-pit mining, however underground mining is also a possibility to access aquamarine reserves. Aquama ... [...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] |
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] |
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] |
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] |
