Phyllosilicate forming distinctive cubic-looking tetragonal crystals in zeolite assemblages. Popular collector mineral. Color: Colorless, white, green, pink. Luster: Vitreous to pearly. Streak: White. Cleavage: Perfect basal. Hardness: 4.5-5. Transparency: Transparent to translucent. Crystal system: Tetragonal. Chemical formula: KCa₄Si₈O₂₀ F,OH ·8H₂O. Specific gravity: 2.33-2.37. Formation: Forms in cavities in basaltic lavas alongside zeolite minerals from late-stage hydrothermal fluids. Common geological settings: India Deccan Traps , Brazil, Iceland, USA; found in basalt vesicles. Common look-alikes and related entries: Stilbite, Calcite, Fluorite.
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Next: Aragonite — Orthorhombic polymorph of calcium carbonate, less stable than calcite. Forms in biological systems shells, pearls and cave deposits.
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
2026-03-30T14:37:36.831186+00:00
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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.
Phyllosilicate forming distinctive cubic-looking tetragonal crystals in zeolite assemblages. Popular collector mineral.
How can you identify Apophyllite?
Compare several properties rather than relying on colour alone. This entry records colour: Colorless, white, green, pink; lustre: Vitreous to pearly; streak: White; Mohs hardness: 4.5-5; cleavage: Perfect basal; crystal system: Tetragonal; transparency: Transparent to translucent. Confirm an important identification with additional field tests or qualified laboratory work.
How does Apophyllite form?
Forms in cavities in basaltic lavas alongside zeolite minerals from late-stage hydrothermal fluids.
Where is Apophyllite commonly found?
India Deccan Traps , Brazil, Iceland, USA; found in basalt vesicles.
What is Apophyllite commonly confused with?
Apophyllite may be confused with Stilbite, Calcite, Fluorite. Compare multiple diagnostic properties because colour and surface appearance can overlap.
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