2.6" Rare Andalucite Var Chiastolite Mineral Specimen Asturias Province Boal Spain
Location: Asturias Province, Boal, Spain
Weight: 5.8 Ounces
Dimensions: 2.6 Inches Long, 1.7 Inches Wide, 1.4 Inches Thick
The item pictured is the one you will receive.
Andalucite, an important mineral within geology and mineralogy, is named after Andalusia in southern Spain, where it was originally discovered and described. This aluminum nesosilicate is distinguished by its unique crystal structure and forms under particular metamorphic conditions. Its occurrence in Spain, especially in the Andalusian region, has been vital for interpreting its geological setting and its function as a key indicator mineral.
Andalucite is one of three polymorphs of Al2SiO5, the other two being kyanite and sillimanite. These polymorphs share the same chemical composition but differ in their crystal structures, which are stable under different pressure and temperature conditions. Andalucite typically forms in medium-grade metamorphic rocks, often associated with regional metamorphism. Its presence indicates a specific range of pressure and temperature conditions during the rock's formation, making it a valuable tool for geologists studying metamorphic processes
Andalucite forms in the orthorhombic crystal system, featuring three axes of different lengths that intersect at right angles. Its crystals typically appear as prisms, often with a square-shaped cross-section. The colors of andalucite are quite diverse, ranging from shades of pink, red, and violet to brown, green, and even clear. This wide spectrum of hues comes from trace elements embedded within its crystal structure. One fascinating variety is chiastolite, known for its unique cross-shaped pattern made by dark carbon-rich inclusions inside the lighter mineral. This striking design occurs during the crystal’s growth, as impurities settle along particular crystallographic paths.
