metamorphic
Unakite
Epidotized Granite
Hardness: 6.0–7.0 Mohs; Color: Mottled green, pink, and gray/white; Luster: Vitreous to dull; Crystal structure: Monoclinic and Trigonal (mixture); Cleavage: Poor/none; Specific Gravity: 2.85–3.20.
- Hardness
- 6
- Color
- Mottled green, pink, and gray/white
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6.0–7.0 Mohs; Color: Mottled green, pink, and gray/white; Luster: Vitreous to dull; Crystal structure: Monoclinic and Trigonal (mixture); Cleavage: Poor/none; Specific Gravity: 2.85–3.20.
Formation & geological history
Formed through hydrothermal metamorphism of granite, where plagioclase feldspar is replaced by epidote. Usually associated with Precambrian or Paleozoic eras in crystalline basement rocks.
Uses & applications
Used primarily as a semi-precious gemstone for cabochons, beads, and carvings. Also used in architectural stone and construction aggregate when found in large quantities.
Geological facts
It was first discovered in the Unaka Range of North Carolina, USA, from which it derives its name. It is the state rock of Virginia.
Field identification & locations
Identify by its unique pistachio-green (epidote) and salmon-pink (orthoclase) mottled appearance. Found in river beds or gravel deposits near metamorphic mountain ranges. Common in the Blue Ridge Mountains of the USA.
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