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Turquoise is an opaque, blue-to-green mineral that is a hydrous phosphate of copper and aluminium, with the chemical formula Cu Al 6 (PO 4) 4 8 ·4H 2 O.It is rare and valuable in finer grades and has been prized as a gemstone for millennia due to its hue.
Turquoise (/ ˈ t ɜːr k (w) ɔɪ z / TUR-k(w)oyz) is a cyan color, based on the mineral of the same name.The word turquoise dates to the 17th century and is derived from the French turquois, meaning 'Turkish', because the mineral was first brought to Europe through Turkey from mines in the historical Khorasan province of Iran (Persia) and Afghanistan today.
Gadolinite; Gahnite; Gahnospinel; Garnet group: Pyralspite. Almandine; Pyrope; Spessartine; Ugrandite. Andradite. Demantoid; Melanite; Topazolite; Grossular ...
This is a list of minerals which have Wikipedia articles. Minerals are distinguished by various chemical and physical properties. Differences in chemical composition and crystal structure distinguish the various species. Within a mineral species there may be variation in physical properties or minor amounts of impurities that are recognized by ...
However, the term prase is also used to describe green quartz and to a certain extent is a color-descriptor, rather than a rigorously defined mineral variety.) Blue-colored chalcedony is sometimes referred to as "blue chrysoprase" if the color is sufficiently rich, though it derives its color from the presence of copper and is largely unrelated ...
Most of the white varieties of turquoise are chalk-like with a Mohs hardness of 1, and are not as hard or durable as howlite, and subsequently require stabilization in order to be used in jewelry, which has resulted in howlite being more popular for use in jewelry than the artificially stabilized white forms of the mineral turquoise.
The IMA-approved mineral faustite [1] is a member of the triclinic turquoise group of hydrous phosphates with the chemical composition ZnAl 6 (PO 4) 4 (OH) 8 ·4H 2 O. It is named after the American mineralogist and petrologist Dr. George Tobias Faust, who workes with the U.S. Geological Survey (USGS). [2] Some divalent copper generally ...
Variscite is a secondary mineral formed by direct deposition from phosphate-bearing water which has reacted with aluminium-rich rocks in a near-surface environment. [6] It occurs as fine-grained masses in nodules, cavity fillings, and crusts. Variscite often contains white veins of the calcium aluminium phosphate mineral crandallite.