metamorphic
Unakite
Epidotized Granite
Hardness: 6.0 to 7.0 (Mohs scale); Color: Mottled green (epidote), pink (orthoclase), and clear/grey (quartz); Luster: Dull to vitreous; Crystal structure: Monoclinic/Orthorhombic (aggregate mixture); Cleavage: Uneven to splintery fracture.
- Hardness
- 6
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6.0 to 7.0 (Mohs scale); Color: Mottled green (epidote), pink (orthoclase), and clear/grey (quartz); Luster: Dull to vitreous; Crystal structure: Monoclinic/Orthorhombic (aggregate mixture); Cleavage: Uneven to splintery fracture.
Formation & geological history
Formed through the hydrothermal metamorphism of granite, where plagioclase feldspar is replaced by epidote. This usually occurs in pre-existing igneous terrains often dating back to the Proterozoic era.
Uses & applications
Used primarily as a lapidary material for beads, cabochons, and decorative carvings. It is also used as an architectural stone and occasionally as construction aggregate.
Geological facts
Unakite is named after the Unaka Range of the Appalachian Mountains in North Carolina/Tennessee where it was first discovered. It is the state rock of Virginia.
Field identification & locations
Identify by its distinctive salmon-pink and pistachio-green mottled appearance. It is commonly found as river pebbles in the Blue Ridge Mountains of the USA and along the shores of Lake Superior.
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