PERIDOT
Peridot: Olivine Gem, Color, Formation & Care
Peridot is the gem variety of olivine, typically yellow-green to olive green. It forms in magnesium-rich igneous rocks and is also found in some meteorites. Its distinctive green color and geological story make it a familiar August birthstone and a popular gem for jewelry.
Table of Contents
Formation and Geological Setting
Peridot occurs in basaltic rocks and mantle-derived materials, where olivine crystallizes from magnesium-rich magma. It can also occur in meteorites called pallasites, in which olivine crystals are embedded in an iron-nickel matrix.
Properties and Appearance
Olivine has a Mohs hardness around 6.5–7 and no prominent cleavage, but peridot can be brittle and may contain fractures. Color ranges from yellow-green to deeper olive green, influenced by iron content.
Identification and Collecting
Peridot can resemble other green gems. Refractive properties, inclusions, and gemological testing help confirm identity. Meteorite-associated peridot should be documented carefully because origin claims require evidence.
Care and Handling
Clean peridot with mild soap, lukewarm water, and a soft brush. Avoid harsh impacts, strong chemicals, and ultrasonic cleaning if fractures are present. Store separately from harder stones.
Frequently Asked Questions
Can color alone confirm identification?
No. Similar minerals and treated materials can overlap in appearance. Use mineralogical references and appropriate testing when certainty matters.
Why is provenance important?
Locality records, seller disclosures, and laboratory reports can support accurate identification and help prevent mislabeling.
Further Reading & Sources
- Mindat — mineral data and localities.
- Handbook of Mineralogy — technical descriptions.
- Gemological Institute of America — gem education.
- Wikipedia: Peridot — background and references.