Rock Identifier
Tumbled epidote or epidote-rich stone (Epidote, Ca₂(Al,Fe)₃(SiO₄)₃(OH); possibly a green jasper or prehnite-epidote aggregate) — mineral
mineral

Tumbled epidote or epidote-rich stone

Epidote, Ca₂(Al,Fe)₃(SiO₄)₃(OH); possibly a green jasper or prehnite-epidote aggregate

AI-generated identification · may be incorrect

Olive-green to brown, translucent in places, with a vitreous-to-waxy luster and visible fibrous/patchy internal structure. Epidote is Mohs 6–7, monoclinic, with distinct cleavage and specific gravity about 3.3–3.5; tumbling obscures crystal form.

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Physical properties

Olive-green to brown, translucent in places, with a vitreous-to-waxy luster and visible fibrous/patchy internal structure. Epidote is Mohs 6–7, monoclinic, with distinct cleavage and specific gravity about 3.3–3.5; tumbling obscures crystal form.

Formation & geological history

Epidote forms chiefly during regional or contact metamorphism and hydrothermal alteration of calcium-rich rocks, commonly in veins and skarns. The specimen is likely a modern polished/tumbled fragment, not an intact crystal.

Uses & applications

Used mainly as a collector mineral and occasional gemstone; epidote-rich rock has little industrial use. Attractive transparent green material may be cabochon-quality, though this small tumbled piece is chiefly ornamental.

Geological facts

Epidote’s green color increases with iron content, producing the characteristic pistachio-green shade. Strong pleochroism can appear in transparent crystals, shifting from yellow-green to brown-green.

Field identification & locations

Common sources include Austria, Pakistan, Mali, Mexico, Norway, and the United States. Confirm with hardness testing, high specific gravity, and comparison with prehnite, serpentine, and green jasper; image identification is not definitive.