Collectible minerals - full range in stock "Quartz"

Quartz is an extremely common rock-forming mineral on the Mohs hardness scale - value 7. It has clear-crystalline and cryptocrystalline forms, which, in turn, contain various varieties of quartz. Diverse in appearance. In Moscow, in the Historical Museum, there is a staff of an Egyptian pharaoh with a knob made of processed veined quartz - 5 thousand years BC. Quartz is the main component of flints, which were processed and used for work by the Neanderthals. At the same time, a transparent variety of quartz, rock crystal, when processed by non-professionals, can be confused with a diamond.

You can see quartz stone for sale and buy it in the Minerals of Russia online store.

Physical properties of Quartz

General
Category	silicate mineral
Formula (repeating unit)	SiO₂
IMA symbol	Qz
Strunz classification	4.DA.05 (oxides)
Dana classification	75.01.03.01 (tectosilicates)
Crystal system	α-quartz: trigonal β-quartz: hexagonal
Crystal class	α-quartz: trapezohedral (class 3 2) β-quartz: trapezohedral (class 6 2 2)
Space group	α-quartz: P3₂21 (no. 154)^[4] β-quartz: P6₂22 (no. 180) or P6₄22 (no. 181)
Unit cell	a = 4.9133 Å, c = 5.4053 Å; Z=3
Identification
Formula mass	60.083 g·mol⁻¹
Color	Colorless through various colors to black
Crystal habit	6-sided prism ending in 6-sided pyramid (typical), drusy, fine-grained to microcrystalline, massive
Twinning	Common Dauphine law, Brazil law and Japan law
Cleavage	{0110} Indistinct
Fracture	Conchoidal
Tenacity	Brittle
Mohs scale hardness	7 – lower in impure varieties (defining mineral)
Luster	Vitreous – waxy to dull when massive
Streak	White
Diaphaneity	Transparent to nearly opaque
Specific gravity	2.65; variable 2.59–2.63 in impure varieties
Optical properties	Uniaxial (+)
Refractive index	n_ω = 1.543–1.545 n_ε = 1.552–1.554
Birefringence	+0.009 (B-G interval)
Pleochroism	None
Melting point	1670 °C (β tridymite) 1713 °C (β cristobalite)
Solubility	Insoluble at STP; 1 ppm_mass at 400 °C and 500 lb/in² to 2600 ppm_mass at 500 °C and 1500 lb/in²
Other characteristics	lattice: hexagonal, Piezoelectric, may be triboluminescent, chiral (hence optically active if not racemic)