2.2" Rare Andalucite Var Chiastolite Mineral Specimen Asturias Province Boal Spain
Location: Asturias Province, Boal, Spain
Weight: 4 Ounces
Dimensions: 2.2 Inches Long, 1.6 Inches Wide, 1.5 Inches Thick
The item pictured is the one you will receive.
Andalucite, a significant mineral in the geological and mineralogical fields, derives its name from Andalusia, a region in southern Spain where it was first identified and described. This aluminum nesosilicate mineral is characterized by its distinctive crystal structure and its formation under specific metamorphic conditions. Its presence in Spain, particularly in the Andalusian region, has been crucial for understanding its geological context and its role as an indicator mineral.
Andalucite is one of three Al2SiO5 polymorphs, alongside kyanite and sillimanite, sharing identical chemical composition but differing in crystal structure, each stable under distinct pressure-temperature conditions. Typically found in medium-grade metamorphic rocks linked to regional metamorphism, andalusite serves as an important indicator of the specific metamorphic environment. It crystallizes in the orthorhombic system, characterized by three mutually perpendicular axes of unequal length, commonly exhibiting prismatic crystals with square cross-sections. Its coloration varies widely—from pink, red, violet, brown, and green to colorless—reflecting trace element variations. The chiastolite variety is distinguished by its unique dark cruciform carbonaceous inclusions formed through directional impurity incorporation during crystal growth.
