What is Prasiolite?
Prasiolite is the green variety of quartz, a sought-after lapidary material whose colour may be natural or produced by controlled heating of amethyst.
Mineralogy and crystal structure
Reference formula: SiO2. Prasiolite is quartz, not a separate mineral species. The page uses a clearly labelled representative quartz structure and distinguishes naturally green material from treated stones. Prasiolite is classified with silicates and has a trigonal crystal system. Typical hardness is 7–7 on the Mohs scale and specific gravity is approximately 2.6–2.7.
Colour, lustre and habit
Typical colours include green, pale green, yellow-green, grey. The usual prismatic, granular, massive habit and vitreous lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Prasiolite forms in or is associated with rare natural quartz occurrences and heat-treated amethyst or citrine in the gem trade. Important documented localities include Brazil, Poland, Canada, the United States and commercial lapidary sources worldwide.
Green quartz with a transparent story
Prasiolite is commercially compelling because colour, treatment and mineral identity intersect. A good guide helps buyers understand why two green quartz stones may have different origins.
Collecting and care
Clean with mild soapy water; avoid sudden heat and disclose treatment history when selling or collecting prasiolite.
