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Quartz is, therefore, classified structurally as a framework silicate mineral and compositionally as an oxide mineral. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. [9] Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation ...
Quartz from Brazil with visible surface staining, sometimes incorrectly identified as citrine. Clear quartz with natural iron inclusions or limonite staining may resemble citrine. [2] However, these crystals will either have coloration only on the surface or in certain spots within the crystal. Quartz that derives its color from coatings or ...
The Nickel–Strunz classifications are 9.F (tectosilicates without zeolitic H 2 O), 9.G (tectosilicates with zeolitic H 2 O), and 4.DA (quartz/silica group). Below is a list of tectosilicate minerals and their chemical formulas, organized by groups and series: Quartz group Quartz – SiO 2; Tridymite – SiO 2; Cristobalite – SiO 2; Coesite ...
A rough specimen of bloodstone. Heliotropes (from Ancient Greek ἥλιος (hḗlios) 'sun' and τρέπειν (trépein) 'to turn') (also called ematille, Indian bloodstones, or simply bloodstones) are aggregate minerals, and cryptocrystalline mixture of quartz that occurs mostly as jasper or sometimes as chalcedony (translucent).
For example, amethyst is a purple variety of the mineral species quartz. Some mineral species can have variable proportions of two or more chemical elements that occupy equivalent positions in the mineral's structure; for example, the formula of mackinawite is given as (Fe,Ni) 9 S 8, meaning Fe x Ni 9-x S 8, where x is a variable number between ...
Varieties of the mineral Quartz. Subcategories. This category has the following 2 subcategories, out of 2 total. C. Chert (3 C, 23 P) Q. Quartz gemstones (2 C, 18 P)
It is governed by the Padang Terap District Council (Malay: Majlis Daerah Padang Terap). Padang Terap District shares a border with Thailand to the north, and with Sik District and Pendang District to the west. It is the third largest district in the State of Kedah, with Kuala Nerang serving as its administrative center.
Kinta District was once famous for its tin, being one of the major tin producers in the 18th century.The discovery of substantial tin deposits in the Kinta Valley attracted a diverse influx of immigrants, particularly from China, who sought their fortunes in the lucrative mining trade.