Alexandrite
Image: Robert M. Lavinsky (CC BY-SA 3.0)
Mineral NameAlexandrite
Chemical FormulaBeAl₂O₄
Mohs Hardness8.5
Crystal Systemorthorhombic
Lustervitreous
Streak Colorwhite
Cleavageimperfect on {110}, distinct on {011}
Fractureconchoidal to uneven
Specific Gravity3.75
Colorsgreen, reddish-purple, yellowish-green, brownish-green
Transparencytransparent
Type LocalityCarnaiba Mine, Pindobaçu, Campo Formoso District, Bahia, Northeast Region, Brazil
Mineral GroupOxides
Usesjewelry, collector
Associated Mineralsquartz, feldspar, mica, beryl, garnet
Rarityrare
Description
A faceted Alexandrite gemstone, known for its remarkable color-change effect, appearing green in daylight and reddish-purple under incandescent light. The image displays a vibrant green specimen.
Geological Context
Alexandrite forms in pegmatites, mica schists, and sometimes in alluvial deposits, requiring the presence of both beryllium and chromium for its unique composition and color-change properties.
