Amazonite
Microcline var. Amazonite · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Triclinic; typically occurs in blocky, prismatic crystals or massive forms; often shows polysynthetic twinning
Mineral Group
Silicates (Tectosilicates); Feldspar Group; Potassium Feldspar Subgroup
Chemical Formula
K(AlSi3O8) with trace amounts of Lead (Pb) or Divalent Iron (Fe2+)
Formation Process
Igneous/Pegmatitic; forms in granitic pegmatites and deep-seated plutonic rocks through slow crystallization
About This Crystal
Opaque to translucent blue-green to turquoise-colored stone with a vitreous to pearly luster. Often features white streaking (exsolution lamellae of albite) and a mottled, blocky appearance.
Physical Characteristics
Color: Green-blue to turquoise; Streak: White; Cleavage: Perfect in two directions at nearly 90 degrees; Fracture: Uneven to splintery; Specific Gravity: 2.56-2.58; Fluorescence: Weak olive-green under UV.
Optical Properties
Refractive Index: 1.522-1.530; Birefringence: 0.008; Optically Biaxial; exhibits a characteristic schiller or pearly sheen due to perthitic texture.
Hardness & Durability
Origin Region
Brazil (Minas Gerais), Russia (Ural Mountains), USA (Colorado), Madagascar, and Ethiopia
Hardness & Durability
Mohs Hardness: 6.0-6.5; Toughness: Poor to fair due to perfect cleavage; brittle stability; sensitive to pressure and high heat.
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid ultrasonic cleaners and steam cleaning; store separately from harder stones like quartz or topaz to prevent scratching.
Rarity & Value
Relatively common; value stems from color saturation (deepest blue-green is prized) and size; usually inexpensive; rarely treated but occasionally dyed to enhance color.
Special Characteristics
Perthitic texture (white streaks caused by albite intergrowth) and occasional weak chatoyancy; color is caused by structural defects associated with lead impurities.
Lore & History
Historically used in Ancient Egypt for jewelry and amulets (found in King Tutankhamun's tomb); traditionally referred to as the 'Stone of Courage' and associated with the Heart and Throat chakras.