Search results
Results from the WOW.Com Content Network
Amethyst is a violet variety of quartz.The name comes from the Koine Greek αμέθυστος amethystos from α - a-, "not" and μεθύσκω (Ancient Greek) methysko / μεθώ metho (Modern Greek), "intoxicate", a reference to the belief that the stone protected its owner from drunkenness. [1]
Formula (repeating unit) SiO 2: IMA symbol: Qz [2 ... Amethyst loses its natural violet color when ... Quartz varieties, properties, crystal morphology. Photos and ...
Amesite is a mineral with general formula of Mg 2 Al 2 SiO 5 (OH) 4. [3] Amesite crystallizes in the triclinic crystal system. [5] It contains three axes of unequal length, not at right angles. It was first described in 1876 for an occurrence in the Chester Emery Mines, Chester, Hampden County, Massachusetts. It was named for mine owner James Ames.
Taaffeite (/ ˈ t ɑː f aɪ t /; BeMgAl 4 O 8) is a mineral, named after its discoverer Richard Taaffe (1898–1967) who found the first sample, a cut and polished gem, in October 1945 in a jeweler's shop in Dublin, Ireland.
Ametrine, also known as trystine, golden amethyst, or by the trade name bolivianite, is a variety of quartz with alternating zones of purple and yellow-orange coloration. Its name is a portmanteau of amethyst and citrine. While ametrine is commonly referred to as a combination of these two quartz varieties, some sources claim this is not ...
Moonstone; General; Category: Anorthoclase variety: Formula (repeating unit) (Na,K)AlSi 3 O 8: Crystal system: Monoclinic: Identification; Color: Can be numerous ...
Although the unit cell is close to being hexagonal in shape ("a" and "c" are nearly equal and β nearly 120°), it is inherently monoclinic and cannot be hexagonal. The crystal structure of coesite is similar to that of feldspar and consists of four silicon dioxide tetrahedra arranged in Si 4 O 8 and Si 8 O 16 rings.
Aragonite is a carbonate mineral and one of the three most common naturally occurring crystal forms of calcium carbonate (Ca CO 3), the others being calcite and vaterite.It is formed by biological and physical processes, including precipitation from marine and freshwater environments.