Prasiolite
Image: Michelle Jo (CC BY 3.0)
Mineral NamePrasiolite
Chemical FormulaSiO2
Mohs Hardness7
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.65
Colorsgreen, light green, dark green
Transparencytransparent
Type LocalityBrazil
Mineral GroupSilicates
Usesjewelry, collector
Associated Mineralsfeldspar, mica, amethyst
Rarityuncommon
Description
These are facet-cut prasiolite gemstones, also known as green quartz, displaying various shades of green from pale to deeper tones, with excellent transparency and brilliance.
Geological Context
Prasiolite is a variety of quartz that forms in igneous and metamorphic rocks. Its green color can be natural, caused by irradiation and iron impurities, or commonly produced by heat-treating amethyst or yellowish quartz.
