metamorphic
Unakite
Epidotized Granite
Hardness: 6-7 (Mohs scale), Color: Mottled green (epidote), pink (orthoclase feldspar), and clear/gray (quartz), Luster: Vitreous to dull, Crystal Structure: Monoclinic/Triclinic mixture, Cleavage: Poor, Specific Gravity: 2.85-3.2
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Physical properties
Hardness: 6-7 (Mohs scale), Color: Mottled green (epidote), pink (orthoclase feldspar), and clear/gray (quartz), Luster: Vitreous to dull, Crystal Structure: Monoclinic/Triclinic mixture, Cleavage: Poor, Specific Gravity: 2.85-3.2
Formation & geological history
Formed through the hydrothermal alteration of granite, where plagioclase feldspar is replaced by epidote. Usually associated with Precambrian or Paleozoic tectonic events.
Uses & applications
Used primarily as a decorative stone, in lapidary work for cabochons and beads, and occasionally as architectural facing or floor tiles.
Geological facts
Unakite was first discovered in the Unaka Range of the Blue Ridge Mountains in the United States. It is the state rock of Virginia.
Field identification & locations
Identify by the distinct 'pistachio green' and 'salmon pink' mottled appearance. It is commonly found in riverbeds as rounded cobbles, particularly in the Appalachian Mountains and the Great Lakes shores.
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