mineral

Pyrite and Calcite (or Barite) Specimen

Iron Sulfide (FeS2) with Calcium Carbonate (CaCO3)

Hardness of 6-6.5 for pyrite and 3 for calcite. Metallic luster for pyrite and pearly to vitreous for calcite. Pyrite forms cubic or pyritohedral crystals, while calcite often forms tabular or bladed crystals (or barite if bladed). Color ranges from brassy yellow to dark metallic gray mixed with white/clear.

Identified August 2, 2026More mineral →

Explore Pyrite and Calcite (or Barite) Specimen in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed in hydrothermal veins, sedimentary rocks, and replacement deposits through low to moderate temperature precipitation from mineral-rich aqueous solutions.

Uses & applications

Prized by mineral collectors and displayed as aesthetic cabinet specimens. Historically used for sulfur and sulfuric acid production, and occasionally in jewelry.

Geological facts

Pyrite is famously known as 'Fool's Gold' due to its metallic golden sheen, though it is harder and more brittle than actual gold. Associations of pyrite with white blade-like crystals are classic examples of multi-mineral hydrothermal specimens.

Field identification & locations

Easily identified by the brassy metallic cubic/granular clusters contrasted against white tabular crystals. Commonly sourced from Peru, Spain, and various localities in the USA.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Soil with Mineral Detritus and Quartz Fragments

Regolith / Silicate Mineral Aggregate

sedimentary

Limonite / Goethite (Iron Ore Mineral nodule)

FeO(OH)·nH2O / FeO(OH)

mineral

Septarian Pebble

Septarian nodule / Concretion

sedimentary

Schist

Metamorphic

Potassium Feldspar (Orthoclase)

Orthoclase (KAlSi3O8)

mineral