mineral

Tumbled green epidote–quartz (probable)

Epidote, Ca₂(Al,Fe³⁺)₃(SiO₄)₃(OH), likely intergrown with quartz and/or chlorite

AI-generated identification · may be incorrect

Small rounded specimen with pistachio to gray-green color, mottled translucent areas, and a dull-to-vitreous luster. Epidote is monoclinic, hardness 6–7, with imperfect cleavage and specific gravity about 3.3–3.5; quartz inclusions are harder (Mohs 7).

Identified August 21, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed in metamorphic rocks, especially altered basalt, greenstone, or blueschist-related veins. The approximate northern California locality is geologically plausible for epidote-bearing metamorphic rocks, though an exact identification requires testing.

Uses & applications

Primarily a collector specimen; attractive polished pieces may be used as cabochons. Epidote has minor ornamental use and no major industrial application.

Geological facts

The yellow-green shade increases with iron content. Epidote commonly occurs with chlorite, actinolite, albite, and quartz in low- to medium-grade metamorphic environments.

Field identification & locations

Field clues include a heavy feel, green pistachio color, and hardness sufficient to scratch glass if epidote-rich. Confirm with a streak, hardness test, and ideally specific gravity or Raman/XRF; similar materials include serpentine, chlorite, and aventurine.