Image: <bdi><a href="https://www.wikidata.org/wiki/Q56247090" class="extiw" title="d:Q56247090"><span title="mineral collector and dealer">Robert M. Lavinsky</span></a></bdi> (CC BY-SA 3.0)
orthorhombiccommonSulfides
Marcasite
FeS2
This specimen displays a pale bronze-yellow color with a distinct metallic luster, forming a radiating or 'coxcomb' crystal habit. Its surface may show some tarnishing.
Marcasite Physical Properties
Mohs Hardness
6Crystal System
orthorhombicLuster
metallicStreak Color
greenish-black to brownish-blackCleavage
poor/indistinct on {101}Fracture
uneven to conchoidalSpecific Gravity
4.8Colors
pale bronze-yellow, tin-white, tarnishes to yellow, brown, iridescentTransparency
opaqueType Locality
Olkusz, Olkusz District, Małopolskie, PolandMineral Group
SulfidesUses
minor ore of sulfur, collector's itemAssociated Minerals
pyrite, galena, sphalerite, calcite, dolomite, bariteRarity
commonGeological Context
Marcasite typically forms in low-temperature, acidic environments, often found in sedimentary rocks, coal seams, and some hydrothermal deposits. It is a polymorph of pyrite, forming under different conditions.
