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Amethyst identification and geology

Amethyst mineral reference specimen

Purple variety of quartz colored by iron impurities and irradiation. Prized as a gemstone since antiquity. Color: Purple to violet. Luster: Vitreous. Streak: White. Cleavage: None conchoidal fracture. Hardness: 7. Transparency: Transparent to translucent. Crystal system: Hexagonal Trigonal. Chemical formula: SiO₂. Specific gravity: 2.65. Formation: Forms in cavities within volcanic rocks, hydrothermal veins, and geodes. Color from Fe³⁺ substitution and natural irradiation. Common geological settings: Brazil, Uruguay, Zambia, South Korea; found in volcanic geodes and hydrothermal veins. Common look-alikes and related entries: Fluorite, Kunzite, Charoite.

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Sources, scope & corrections

These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.

Editorial owner
GeoMiner
Last updated
2026-03-30T14:36:39.363387+00:00
Review status
Published; not independently peer-reviewed
  • IMA–CNMNC List of Mineral Names — International Mineralogical Association. Official mineral-name, nomenclature, and classification records.
  • Mineral ID Key — Mineralogical Society of America. Physical-property identification methods, repeat-testing guidance, and limitations.

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Common questions

What is Amethyst?
Purple variety of quartz colored by iron impurities and irradiation. Prized as a gemstone since antiquity.
How can you identify Amethyst?
Compare several properties rather than relying on colour alone. This entry records colour: Purple to violet; lustre: Vitreous; streak: White; Mohs hardness: 7; cleavage: None conchoidal fracture; crystal system: Hexagonal Trigonal; transparency: Transparent to translucent. Confirm an important identification with additional field tests or qualified laboratory work.
How does Amethyst form?
Forms in cavities within volcanic rocks, hydrothermal veins, and geodes. Color from Fe³⁺ substitution and natural irradiation.
Where is Amethyst commonly found?
Brazil, Uruguay, Zambia, South Korea; found in volcanic geodes and hydrothermal veins.
What is Amethyst commonly confused with?
Amethyst may be confused with Fluorite, Kunzite, Charoite. Compare multiple diagnostic properties because colour and surface appearance can overlap.

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