gemstone
Amethyst
Silicon Dioxide with iron impurities (SiO2)
Hardness: 7 on Mohs scale; Color: purple to violet; Luster: Vitreous; Crystal structure: Hexagonal (trigonal); Cleavage: None; Specific gravity: 2.65.
- Hardness
- 7 on Mohs scale
- Color
- purple to violet
- Luster
- Vitreous
Identified More gemstone →
Explore Amethyst in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 on Mohs scale; Color: purple to violet; Luster: Vitreous; Crystal structure: Hexagonal (trigonal); Cleavage: None; Specific gravity: 2.65.
Formation & geological history
Forms in hydrothermal veins and basaltic cavities (geodes). The purple color comes from irradiation of iron impurities within the quartz crystal lattice. Specimens range from thousands to millions of years old.
Uses & applications
Primarily used in jewelry (rings, necklaces, earrings), as decorative specimens for collectors, and in alternative healing practices.
Geological facts
Until the 18th century, amethyst was included in the cardinal gemstones, considered as valuable as diamond or ruby, until large deposits were found in Brazil.
Field identification & locations
Identify by its distinctive purple hue and hexagonal crystal habit. Found globally, with major deposits in Brazil, Uruguay, Zambia, and Canada. Look for glass-like luster and lack of cleavage planes.
More like this
Other gemstone specimens
Cubic Zirconia (simulant) or Diamond
ZrO2 (Cubic Zirconia) or C (Diamond)
gemstone
Ammolite
Ammolite (Biogenic Aragonite with trace elements; fossils of Placenticeras meeki and Placenticeras intercalare)
mineral
Cubic Zirconia (or possibly Diamond)
Zirconium dioxide (or Carbon)
gemstone
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
sedimentary
Faceted Gemstone
Unknown transparent mineral, possibly Diamond (C), Cubic Zirconia (ZrO2), Quartz (SiO2), or Glass
gemstone
Milky Quartz
Silicon Dioxide (SiO2)
mineral