Unakite
Unakite (Epidotized Granite) · Semi-Precious Gemstone / Decorative Stone
Crystal System
Monoclinic (Epidote) and Triclinic (Feldspar); typically occurs in a massive, phaneritic habit as an altered rock.
Mineral Group
Silicates (primarily a combination of Epidote, Orthoclase Feldspar, and Quartz)
Chemical Formula
KAlSi3O8 + Ca2(Al,Fe)3(SiO4)3(OH) + SiO2
Formation Process
Metamorphic; specifically through hydrothermal alteration where plagioclase feldspar is replaced by epidote within granitic rocks.
About This Crystal
A mottled metamorphic rock characterized by a distinctive combination of moss-green epidote and salmon-pink orthoclase feldspar, often interspersed with clear to grey quartz. It is opaque with a vitreous to dull luster and a coarse-grained texture.
Physical Characteristics
Color: Pink and Green; Streak: White; Cleavage: None (in rock form); Fracture: Uneven to conchoidal; Specific Gravity: 2.85–3.20; Fluorescence: Generally none, though some feldspars may show weak luminescence.
Optical Properties
As a rock, it does not have a single refractive index. The individual components exhibit different optical properties: Orthoclase (RI 1.52), Epidote (RI 1.73), and Quartz (RI 1.54). It is opaque and lacks pleochroism as a whole.
Hardness & Durability
Origin Region
Notably the Unaka Mountains of North Carolina and Tennessee (USA); also found in South Africa, Sierra Leone, Brazil, and China.
Hardness & Durability
Mohs hardness ranges from 6 to 7. It is durable and tough, suitable for jewelry usage, though the different hardness of the constituent minerals can make polishing to a uniform shine challenging.
Care & Maintenance
Clean with warm soapy water and a soft cloth. Avoid harsh chemicals and ultrasonic cleaners which may penetrate micro-fractures in the rock's boundary layers.
Rarity & Value
Common; very affordable. Value is determined by the balance of color (ideally a 50/50 split of pink and green) and the quality of the polish. Rarely treated.
Special Characteristics
Known for its unique 'pistachio and salmon' aesthetic; occasionally contains trace amounts of magnetite or zircon inclusions.
Lore & History
Discovered in the Unaka Range (USA) and often associated with balance and grounding. In traditional lore, it is frequently used in 'fertility' practices or for emotional healing, specifically to balance the heart chakra. Historically used as a building stone and for carving ornamental objects.