Unakite
Unakite (Metamorphic Rock / Altered Granite) · Semi-Precious Gemstone / Decorative Stone
Crystal System
Monoclinic (Epidote), Monoclinic (Orthoclase), Trigonal (Quartz); Habit is massive or granular.
Mineral Group
Silicates (Group: Rock composed primarily of Epidote, Feldspar, and Quartz)
Chemical Formula
Complexity of Ca2(Al,Fe)3(SiO4)3(OH) [Epidote] + KAlSi3O8 [Orthoclase] + SiO2 [Quartz]
Formation Process
Metamorphic; specifically hydrothermal alteration of granite where plagioclase feldspar is replaced by epidote.
About This Crystal
A mottled, opaque stone featuring a distinct green and pink/red-orange color palette. The green portions exhibit a pistachio hue with a dull-to-vitreous luster, while the pink/red areas represent orthoclase feldspar. This specimen is polished into a smooth, rounded cabochon or worry stone shape.
Physical Characteristics
Color: Pistachio green, salmon pink, and grey; Streak: White; Cleavage: None (rock mass); Fracture: Uneven to conchoidal; Specific Gravity: 2.85–3.20; Fluorescence: Generally none, though feldspar may exhibit weak red or orange.
Optical Properties
Opaque; Refractive Index: Variable (approx 1.52-1.76 depending on mineral concentration); Birefringence: Not applicable to massive rock; luster: Vitreous when polished.
Hardness & Durability
Origin Region
Unaka Range (North Carolina/Tennessee, USA), South Africa, Sierra Leone, Brazil, and China.
Hardness & Durability
Mohs Hardness: 6–7; Toughness: Fair to Good; Stability: Stable under normal conditions, though heat may affect the pink feldspar.
Care & Maintenance
Safe to clean with warm soapy water and a soft brush. Avoid ultrasonic cleaners and harsh chemicals. Store separately to prevent scratching softer stones or being scratched by harder ones.
Rarity & Value
Common; Value is generally low, based primarily on the attractiveness of the color patterning and quality of the polish. No common treatments.
Special Characteristics
Characterized by its unique 'pistachio and ham' appearance caused by the intergrowth of green epidote and pink feldspar.
Lore & History
Named after the Unaka Mountains in the United States where it was first discovered. In metaphysical traditions, it is often associated with the Heart Chakra and believed to promote balance, grounding, and emotional release; these are cultural beliefs rather than scientific facts.