Aquamarine
Image: Robert M. Lavinsky (CC BY-SA 3.0)
Mineral NameAquamarine
Chemical FormulaBe₃Al₂Si₆O₁₈
Mohs Hardness7.5
Crystal Systemhexagonal
Lustervitreous
Streak Colorwhite
Cleavageimperfect basal
Fractureconchoidal to uneven
Specific Gravity2.68
Colorsblue, greenish-blue
Transparencytransparent
Type LocalityErongo Mountain, Usakos and Omaruru Districts, Erongo Region, Namibia
Mineral GroupSilicates (Cyclosilicates)
Usesjewelry, collector
Associated Mineralsschorl, feldspar, quartz, mica
Rarityuncommon
Description
This specimen features a prominent, well-formed, transparent blue aquamarine crystal, characteristic of the beryl group, growing alongside dark, opaque schorl (black tourmaline). The aquamarine exhibits a prismatic habit with a distinct hexagonal cross-section.
Geological Context
Aquamarine typically forms in granitic pegmatites and hydrothermal veins, often associated with other pegmatite minerals like feldspar, quartz, and various tourmalines. Its blue color is due to iron impurities within the beryl structure.
