metamorphic
Unakite
Epidotized Granite (Fe, Ca, Al silicate + KAlSi3O8)
Hardness: 6-7 (Mohs); Color: Pink and pistachio green mottled; Luster: Vitreous to dull; Crystal structure: Monoclinic (epidote) and Monoclinic/Triclinic (feldspar); Specific gravity: 2.85-3.20.
- Hardness
- 6-7 (Mohs)
- Color
- Pink and pistachio green mottled
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6-7 (Mohs); Color: Pink and pistachio green mottled; Luster: Vitreous to dull; Crystal structure: Monoclinic (epidote) and Monoclinic/Triclinic (feldspar); Specific gravity: 2.85-3.20.
Formation & geological history
Formed through the hydrothermal metamorphism of granite, where plagioclase feldspar is replaced by epidote. Usually associated with Precambrian or Paleozoic geological ages.
Uses & applications
Used primarily as a decorative stone, in lapidary work for cabochons, beads, and carvings. Also used occasionally as architectural stone or gravel.
Geological facts
First discovered in the Unaka Range of North Carolina, USA, from which it takes its name. It is the state rock of Virginia.
Field identification & locations
Identified by its unique 'Christmas-like' color combination of pink orthoclase and green epidote. Often found as pebbles in river beds or glacial till in the Blue Ridge Mountains and Lake Superior regions.
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