Amethyst is a purple or lilac variety of the mineral quartz. It is translated from Greek as "not to be drunk", because it was believed that this stone protects against drunkenness. Transparent amethysts are semi-precious stones and have been used in jewelry from ancient times to the present day. The color of amethyst is determined by the ferrous iron contained in it, which is incorporated into the crystal lattice at the molecular level. Amethyst is one of the most popular collectible minerals.
You can see amethyst stone for sale and buy it in the Minerals of Russia online store.
General | |
---|---|
Category | Silicate mineral |
Formula (repeating unit) |
Silica (silicon dioxide, SiO2) |
Crystal system | Trigonal |
Crystal class | Trapezohedral (32) |
Space group | P3221 (no. 154) |
Identification | |
Color | Purple, violet, dark purple |
Crystal habit | 6-sided prism ending in 6-sided pyramid (typical) |
Twinning | Dauphine law, Brazil law, and Japan law |
Cleavage | None |
Fracture | Conchoidal |
Mohs scale hardness | 7–lower in impure varieties |
Luster | Vitreous/glassy |
Streak | White |
Diaphaneity | Transparent to translucent |
Specific gravity | 2.65 constant; variable in impure varieties |
Optical properties | Uniaxial (+) |
Refractive index | nω = 1.543–1.553 nε = 1.552–1.554 |
Birefringence | +0.009 (B-G interval) |
Pleochroism | Weak to moderate purple/reddish purple |
Melting point | 1650±75 °C |
Solubility | Insoluble in common solvents |
Other characteristics | Piezoelectric |