Heliodor
Image: <a href="//commons.wikimedia.org/wiki/User:EvaK" title="User:EvaK">Eva K.</a> (GFDL 1.2)
Mineral NameHeliodor
Chemical FormulaBe₃Al₂Si₆O₁₈
Mohs Hardness7.5
Crystal Systemhexagonal
Lustervitreous
Streak Colorwhite
Cleavageimperfect basal {0001}
Fractureconchoidal to uneven
Specific Gravity2.69
Colorsgolden-yellow, yellowish-green
Transparencytransparent
Type LocalityBrazil, Namibia, Madagascar, Ukraine
Mineral GroupSilicates (Cyclosilicates)
Usesjewelry, collector
Associated Mineralsquartz, feldspar, mica, tourmaline
Rarityuncommon
Description
This image features a transparent, golden-yellow hexagonal crystal of Heliodor, a variety of beryl, prominently displayed within a matrix of dark, flaky minerals, likely mica, and some lighter, granular material.
Geological Context
Heliodor typically forms in granitic pegmatites and hydrothermal veins, often associated with other pegmatitic minerals. Its characteristic yellow color is due to trace amounts of iron (Fe³⁺) within the crystal structure.
