Unakite
Unakite (Epidotized Granite) · Semi-Precious Gemstone / Metamorphic Rock
Crystal System
Monoclinic (Epidote) and Triclinic (Feldspar); typically occurs in a massive, phaneritic igneous habit.
Mineral Group
Silicates (specifically a rock composed of Feldspar, Epidote, and Quartz)
Chemical Formula
KAlSi3O8 + Ca2(Al,Fe)3(SiO4)3(OH) + SiO2
Formation Process
Metamorphic/Hydrothermal: Forms when granite is altered by hydrothermal activity, transforming pyroxene and amphibole into epidote.
About This Crystal
An opaque stone characterized by a mottled, moss-like appearance blending pistachio green epidote, salmon-pink orthoclase feldspar, and clear to grey quartz. It has a dull to vitreous luster when polished.
Physical Characteristics
Color: Green and pink mottled; Streak: White; Cleavage: None (rock mass); Fracture: Uneven to conchoidal; Specific Gravity: 2.85–3.20; Fluorescence: Generally none.
Optical Properties
Opaque; No pleochroism or birefringence visible in hand specimen due to aggregate nature; Refractive Index: Approx. 1.52 (Feldspar) to 1.73 (Epidote).
Hardness & Durability
Origin Region
Unaka Mountains (USA), South Africa, Sierra Leone, Brazil, and China; found in hydrothermal alteration zones.
Hardness & Durability
Mohs Hardness: 6.0–7.0; Toughness: Good; Stability: Stable under normal light and heat, though chemicals can affect the different minerals unevenly.
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid ultrasonic cleaners and harsh chemicals; store separately to prevent scratching softer stones.
Rarity & Value
Common; relatively inexpensive; value is determined by the balance and vibrancy of the pink and green colors and quality of polish.
Special Characteristics
Displays a unique 'granitic' texture with patchy color distribution; may contain minor inclusions of magnetite or zircon.
Lore & History
First discovered in the Unaka Range of North Carolina; traditionally known as a stone of vision and balance, associated with the heart chakra and grounding energies.