Marcasite Details

Marcasite Information and Occurrences

Chemical Properties

• Chemical Formula: FeS2
• Composition: Iron sulfide, often with some arsenic and nickel
• Crystal System: Orthorhombic
• Hardness: 6-6.5
• Cleavage: Poor/Indistinct
• Luster: Metallic
• Color: Pale brass-yellow, sometimes with a greenish tint, tarnishes darker

• Physical Properties

• Density: 4.8-4.9 g/cm3
• Streak: Greenish-black
• Diaphaneity: Opaque
• Fracture: Irregular/Uneven
• Habit: Crystals are commonly tabular or prismatic, striated, often with curved faces, also massive, nodular, and stalactitic.

Occurrences

Marcasite is a common and widespread mineral. It occurs in many sedimentary, metamorphic, and igneous rocks as well as in hydrothermal veins and replacement deposits. Some of the notable occurrences include:

• Germany: Hesse, Black Forest, Upper Harz Mountains, and Erzgebirge
• France: Alsace, Lorraine, and Auvergne
• Spain: Rio Tinto Mines, Andalusia
• USA: Illinois, Missouri, Oklahoma, and Colorado
• Canada: Quebec, Nova Scotia, and Ontario
• China: Inner Mongolia, Guangdong, and Hunan
• Australia: Queensland and Tasmania