mineral
Amethyst Cluster
Silicon Dioxide (Quartz variety), SiO2
Hardness of 7 on the Mohs scale; color ranges from pale lilac to deep purple; vitreous (glassy) luster; trigonal crystal system; exhibits conchoidal fracture with no true cleavage; specific gravity of 2.65.
Identified More mineral →
Explore Amethyst Cluster in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 7 on the Mohs scale; color ranges from pale lilac to deep purple; vitreous (glassy) luster; trigonal crystal system; exhibits conchoidal fracture with no true cleavage; specific gravity of 2.65.
Formation & geological history
Forms within gas cavities (vesicles) in volcanic rocks or hydrothermal veins, where silica-rich solutions deposit crystalline quartz over long periods, often colored by iron impurities and natural irradiation.
Uses & applications
Widely used in jewelry, decorative items, lapidary arts, and valued by crystal collectors and spiritual practitioners.
Geological facts
Amethyst was once as valuable as ruby and emerald until extensive deposits were discovered in Brazil. Its purple color comes from trace amounts of iron interacting with natural gamma irradiation.
Field identification & locations
Easily identified by its distinctive purple coloration and hexagonal crystal terminations. Found worldwide, including notable occurrences in the southwestern United States and Brazil.
More like this
Other mineral specimens
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Soil with Mineral Detritus and Quartz Fragments
Regolith / Silicate Mineral Aggregate
sedimentary
Limonite / Goethite (Iron Ore Mineral nodule)
FeO(OH)·nH2O / FeO(OH)
mineral
Septarian Pebble
Septarian nodule / Concretion
sedimentary
Schist
Schist
Metamorphic
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral