Emerald
Image: Robert M. Lavinsky (CC BY-SA 3.0)
Mineral NameEmerald
Chemical FormulaBe₃Al₂(SiO₃)₆
Mohs Hardness7.5
Crystal Systemhexagonal
Lustervitreous
Streak Colorwhite
Cleavageimperfect basal
Fractureconchoidal to uneven
Specific Gravity2.67
Colorsgreen
Transparencytransparent to translucent
Type LocalityKagem Emerald Mine, Kafubu Emerald District, Ndola, Copperbelt Province, Zambia
Mineral GroupSilicates
Usesjewelry, collector
Associated Mineralsquartz, beryl
Rarityrare
Description
This specimen features several vibrant green emerald crystals, some exhibiting well-formed hexagonal prismatic habits, embedded within a matrix of white quartz. The emeralds display varying degrees of clarity and intensity of green color.
Geological Context
Emeralds are a variety of beryl colored by trace amounts of chromium and/or vanadium, typically forming in metamorphic rocks such as schists or in hydrothermal veins and pegmatites associated with granitic intrusions. Their formation requires specific geological conditions to concentrate the necessary elements.
