metamorphic
Unakite
Altered Granite (Epidotized Granite)
Hardness: 6 to 7 on the Mohs scale. Color: Mottled shades of green (epidote), pink (orthoclase feldspar), and white/clear (quartz). Luster: Vitreous to dull. Crystal structure: Granular, massive (phaneritic texture). Cleavage: None distinct. Specific gravity: 2.6 to 2.8.
- Hardness
- 6 to 7 on the Mohs scale
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6 to 7 on the Mohs scale. Color: Mottled shades of green (epidote), pink (orthoclase feldspar), and white/clear (quartz). Luster: Vitreous to dull. Crystal structure: Granular, massive (phaneritic texture). Cleavage: None distinct. Specific gravity: 2.6 to 2.8.
Formation & geological history
Forms through hydrothermal alteration of granite, where hot fluids alter the original feldspar and plagioclase minerals into pink orthoclase and green epidote, frequently alongside quartz. It is a metamorphic alteration product of an igneous parent rock.
Uses & applications
Used primarily in lapidary arts for making cabochons, beads, polished stones, small carvings, and decorative ornaments.
Geological facts
Unakite was first discovered in the Unaka Mountains of western North Carolina, which is where it gets its name. It is commonly found as glacial drift pebbles or in stream gravels where weathering has eroded the parent rock.
Field identification & locations
Easily identified in the field by its distinct and striking combination of salmon-pink and pistachio-green patches. Common localities include the Blue Ridge Mountains in the USA, South Africa, Brazil, and China.
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