metamorphic
Epidote in Matrix (Unakite-like Rock Fragment)
Epidote (Ca2(Al,Fe)3(SiO4)3(OH)) / Altered Metamorphic Pebble
Hardness 6-7, pistachio green to dark brownish-grey in color, vitreous to dull luster, monoclinic crystal structure in raw forms, dense fine-grained matrix with yellowish-green patches.
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Physical properties
Hardness 6-7, pistachio green to dark brownish-grey in color, vitreous to dull luster, monoclinic crystal structure in raw forms, dense fine-grained matrix with yellowish-green patches.
Formation & geological history
Formed through low-to-medium grade regional or contact metamorphism and hydrothermal alteration of plagioclase-rich igneous rocks, particularly granites or basalts.
Uses & applications
Used primarily for lapidary rough, tumbling, educational specimens, and minor decorative stone carving when present in larger or higher-grade quantities.
Geological facts
Epidote gets its characteristic 'pistachio green' color from iron substituting for aluminum in its crystal structure. Small pebbles often show alteration rims and mixed mineral grains like quartz and feldspar.
Field identification & locations
Identified in the field by its distinctive yellowish-green spots or veins embedded in a darker greyish or pink matrix. Commonly found in riverbeds, glacial tills, and metamorphic terrains worldwide.
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