Calcium aluminum phyllosilicate with a distinctive apple-green color. One of the first minerals to be named after a person. Color: Pale green, yellow, white. Luster: Vitreous to pearly. Streak: White. Cleavage: Good in one direction. Hardness: 6-6.5. Transparency: Translucent. Crystal system: Orthorhombic. Chemical formula: Ca₂Al₂Si₃O₁₀ OH ₂. Specific gravity: 2.80-2.95. Formation: Forms in cavities in basaltic lavas and in low-grade metamorphic rocks from hydrothermal fluids. Common geological settings: South Africa, Australia, USA, China; found in basalt cavities and zeolite zones. Common look-alikes and related entries: Jade, Chrysoprase, Smithsonite.
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.
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GeoMiner
Last updated
2026-03-30T14:36:56.136369+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.
Calcium aluminum phyllosilicate with a distinctive apple-green color. One of the first minerals to be named after a person.
How can you identify Prehnite?
Compare several properties rather than relying on colour alone. This entry records colour: Pale green, yellow, white; lustre: Vitreous to pearly; streak: White; Mohs hardness: 6-6.5; cleavage: Good in one direction; crystal system: Orthorhombic; transparency: Translucent. Confirm an important identification with additional field tests or qualified laboratory work.
How does Prehnite form?
Forms in cavities in basaltic lavas and in low-grade metamorphic rocks from hydrothermal fluids.
Where is Prehnite commonly found?
South Africa, Australia, USA, China; found in basalt cavities and zeolite zones.
What is Prehnite commonly confused with?
Prehnite may be confused with Jade, Chrysoprase, Smithsonite. Compare multiple diagnostic properties because colour and surface appearance can overlap.
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