Amazonite
Microcline var. Amazonite · Semi-Precious Gemstone and Decorative Stone
Crystal System
Triclinic, commonly found as massive or tabular crystals with well-developed cleavage planes and twinning.
Mineral Group
Silicates (Tectosilicates)
Chemical Formula
KAlSi3O8
Formation Process
Igneous and pegmatitic formation, crystallizing slowly from cooling magma rich in water and incompatible elements, at moderate to high temperatures.
About This Crystal
A tumbled, smooth specimen displaying a characteristic bright turquoise-green to blue-green color with characteristic whitish grid-like or mottled streaks (albite lamellae). It is opaque with a vitreous to waxy luster on polished surfaces and includes patches of dark matrix material.
Physical Characteristics
Color ranges from bright green to blue-green. Streak is white. Two directions of good cleavage meeting at nearly 90 degrees. Fracture is uneven to conchoidal. Specific gravity is approximately 2.56. Brittle tenacity. Generally inert under UV light.
Optical Properties
Biaxial negative with a refractive index between 1.514 and 1.530. Birefringence is low (around 0.008). Displays weak pleochroism and occasionally a subtle sheen or aventurescence due to microscopic inclusions.
Hardness & Durability
Origin Region
Notable sources include Russia (Ilmen Mountains), the United States (Colorado), Madagascar, Brazil, and Namibia. Typically forms in granitic pegmatites.
Hardness & Durability
Mohs hardness of 6 to 6.5. Moderate toughness, but vulnerable to breakage along distinct cleavage planes if impacted. Requires care in jewelry settings.
Care & Maintenance
Clean with warm soapy water using a soft cloth or brush. Avoid ultrasonic cleaners, steam, harsh acids, and prolonged exposure to direct sunlight or high heat to prevent color fading.
Rarity & Value
Common to uncommon. Value depends on intense, saturated blue-green color, lack of heavy white striping or dark impurities, and large size. Prices are generally affordable for tumbling and carving grades.
Special Characteristics
Displays characteristic grid-like twinning (albite twinning) visible as white striations on the surface, known as tartan twinning. Color is historically attributed to lead or water, though modern studies point to irradiation-induced defects involving lead and structural water.
Lore & History
Named after the Amazon River, though no deposits are known to occur there. Historically used in ancient Mesopotamia and by ancient Egyptians for jewelry and amulets. In metaphysical practices, it is known as the 'stone of courage and truth', associated with the heart and throat chakras.