Global Gemology - Rare Gems & Jewels
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PYRITE

Picture
Vintage, German-made sterling silver & marcasite brooch
The "marcasite" in this butterfly brooch is actually pyrite.
Species:  Pyrite
​​Mohs Hardness:  6 to 6.5 out of 10
Color:  Opaque, metallic gold or silver
RI:  OTL
Birefringence:  Too opaque to test
SR/DR/AGG:  SR
Fluorescence:  Inert
SG:  5.00 (+/-0.10)
Routine Treatments:  None

Pyrite Facts

Picture
Vintage sterling silver and marcasite brooch by CPS of Birmingham, England
Vintage ribbon brooch set with "marcasite" (pyrite)

Pyrite, often incorrectly referred to as marcasite, is a metallic gem with a brassy or silvery appearance.

Pyrite is typically faceted into rose cuts and set in sterling silver jewelry.

Pyrite is also known as "fool's gold", due to its golden metallic luster.

Marcasite has an unstable crystal structure, causing it to crumble or break apart rather easily.

In some cases, marcasite will react with moisture in the air, creating sulfuric acid.  For these reasons, marcasite is never used in jewelry.


You can almost always assume "marcasite" in jewelry is actually pyrite.


All photos courtesy of Scott Papper, GIA GG, AJP, CMA (NAJA)

  • HOME
  • ABOUT
  • SHOP
  • SERVICES
    • APPRAISALS
    • EXPERT WITNESS TESTIMONY
    • SELL YOUR JEWELRY
  • GEMOLOGY
    • GEM ENCYCLOPEDIA
    • THE ART OF GEMOLOGY
  • JEWELRY EDUCATION
    • DIAMOND FACTS
    • JEWELER DIRECTORY
    • JEWELRY PERIODS
    • POCKET WATCHES
    • NATIVE AMERICAN JEWELRY
  • GLOSSARY