metamorphic
Unakite-like epidote–feldspar rock
Epidote + K-feldspar/plagioclase ± quartz; compositionally similar to unakite
AI-generated identification · may be incorrectTypically green epidote, pink to salmon feldspar, and gray-white quartz; opaque, mottled, granular texture with vitreous to dull luster. Hardness is approximately 6–7 Mohs; no obvious cleavage is visible in the specimen, and specific gravity is commonly about 2.7–3.3.
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Physical properties
Typically green epidote, pink to salmon feldspar, and gray-white quartz; opaque, mottled, granular texture with vitreous to dull luster. Hardness is approximately 6–7 Mohs; no obvious cleavage is visible in the specimen, and specific gravity is commonly about 2.7–3.3.
Formation & geological history
Unakite forms when granitic rock is hydrothermally altered, converting dark minerals and plagioclase partly to epidote while retaining pink feldspar and quartz. It is generally Precambrian to Paleozoic in age, depending on locality; this hand specimen’s exact origin cannot be determined from the image.
Uses & applications
Used as a decorative and lapidary stone for tumbled stones, cabochons, carvings, and bookends; occasionally used as aggregate. Typical rough or polished pieces have modest collector value.
Geological facts
The characteristic pink-and-green color contrast results from intergrown feldspar and epidote. The pictured material may also be epidote-rich altered granite or another red-green metamorphic rock rather than strict unakite.
Field identification & locations
Identify it by its mottled salmon-pink and pistachio-green colors, hard granular texture, and lack of glassy conchoidal fracture; a streak, hardness, and thin-section test would help confirm it. Common sources include the Unaka Mountains of Tennessee and North Carolina, plus similar altered granites worldwide.
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