Amazonite
Microcline var. Amazonite · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Triclinic; often occurs in blocky, prismatic crystals or massive, granular habits with characteristic lamellar twinning
Mineral Group
Silicates (Tectosilicates); Feldspar group; Alkali Feldspar subgroup
Chemical Formula
K(AlSi3O8), colored by trace amounts of lead (Pb) and water (H2O)
Formation Process
Igneous/Pegmatitic; forms from the slow cooling of residual magma in granitic pegmatites, often alongside smoky quartz and schorl
About This Crystal
Medium to light green or turquoise-blue color, opaque to translucent with a vitreous to pearly luster. Often displays a characteristic white mottled or streaked pattern due to albite exsolution lamellae (perthitic texture).
Physical Characteristics
Color ranges from pale green to deep blue-green with a white streak. Possesses perfect cleavage in two directions at nearly 90 degrees. Specific gravity is approximately 2.56-2.58. Generally non-fluorescent, but may show weak green or olive under UV.
Optical Properties
Refractive index 1.522-1.530; Biaxial negative; exhibits low birefringence. A characteristic optical effect is a faint schiller or pearly sheen on cleavage planes due to internal twinning/exsolution.
Hardness & Durability
Origin Region
Prominent sources include Colorado (Pikes Peak), USA; Minas Gerais, Brazil; Ural Mountains, Russia; and Ethiopia; typically found in granitic pegmatites
Hardness & Durability
Mohs hardness of 6 to 6.5. It is somewhat brittle with a splintery fracture and perfect cleavage, making it susceptible to cracking if struck hard.
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid ultrasonic cleaners and steam cleaning due to cleavage planes. Protect from harsh chemicals and sudden temperature changes.
Rarity & Value
Relatively common in lower grades; deep, saturated blue-green specimens with sharp crystal forms are highly valued by collectors. Often used for cabochons and beads.
Special Characteristics
Perthitic texture (white streaks caused by albite intergrowth) is a diagnostic feature. It serves as a classic example of color caused by lead impurities in a silicate lattice.
Lore & History
Named after the Amazon River, though no true deposits are found in the river itself. Used in ancient Egypt for amulets and jewelry (found in Tutankhamun's tomb). Traditionally associated with the heart and throat chakras, symbolizing balance, truth, and calming energy.