Moonstone
Image: <a rel="nofollow" class="external text" href="https://www.flickr.com/people/25326737@N00">Jarno</a> from Rotterdam, Netherlands (CC BY 2.0)
Mineral NameMoonstone
Chemical Formula(Na,K)AlSi3O8
Mohs Hardness6
Crystal Systemmonoclinic
Streak Colorwhite
Cleavageperfect in two directions (feldspar cleavage)
Fractureuneven to conchoidal
Specific Gravity2.56
Colorsyellowish-white, peach, gray, blue, colorless
Transparencytranslucent
Type LocalityIndia
Mineral Groupsilicates
Usesjewelry, ornamental, collector
Associated Mineralsquartz, feldspar, mica
Rarityuncommon
Description
The image displays two tumbled moonstone pieces, exhibiting a soft, internal glow known as adularescence. They are predominantly yellowish-white to peach in color, with some subtle banding and minor darker inclusions.
Geological Context
Moonstone is a variety of feldspar, typically orthoclase or albite, that forms in igneous and metamorphic rocks, often in pegmatites. Its characteristic adularescence is caused by the scattering of light between microscopic, alternating layers of different feldspar minerals.
