metamorphic
Unakite
Altered Granite (Epidotized Granite)
Hardness: 6-7 on the Mohs scale; Color: Mottled shades of pink (orthoclase feldspar), green (epidote), and clear/white (quartz); Luster: Vitreous to sub-vitreous; Crystal structure: Triclinic (feldspar) and monoclinic (epidote); Cleavage: Perfect in two directions for feldspar; Specific gravity: 2.6-3.0
- Hardness
- 6-7 on the Mohs scale
- Luster
- Vitreous to sub-vitreous
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Physical properties
Hardness: 6-7 on the Mohs scale; Color: Mottled shades of pink (orthoclase feldspar), green (epidote), and clear/white (quartz); Luster: Vitreous to sub-vitreous; Crystal structure: Triclinic (feldspar) and monoclinic (epidote); Cleavage: Perfect in two directions for feldspar; Specific gravity: 2.6-3.0
Formation & geological history
Formed through the hydrothermal alteration of standard granite, where original plagioclase feldspar is replaced by epidote. This metasomatic process typically occurs within fractures or shear zones deep within the Earth's crust over millions of years.
Uses & applications
Widely used in lapidary arts for cabochons, polished spheres, tumbled stones, beads, and carved decorative items due to its appealing mottled appearance.
Geological facts
Unakite was first discovered in the Unaka Mountains of North Carolina, from which it derives its name. It is often found in glacial drift pebbles and cobbles originating from mountain-building events.
Field identification & locations
Easily identified visually by its distinctive, vibrant mix of pink feldspar and green epidote. Commonly found in regions with ancient granitic mountain ranges or as pebbles in glacial outwash; popular among beginner and intermediate rockhounds.
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