Guide
Marcasite specimens for sale
70 for sale · $35–$7,500 USD
199 in the gallery
Marcasite is a sulfide mineral with the formula FeS2. It commonly forms tabular and prismatic crystals that can display a metallic to pale-brass luster, often weathering into a brunneous patina. Crystals can occur in clusters, as twinned forms, or as radiating aggregates, and the mineral’s distinctive shine under reflected light makes sharp facets appealing to collectors.
- Formula
- FeS2
- Rarity
- Common
- Stability
- Unstable
- Collector interest
- Moderate Interest
- Classification notes
- Sulfides; Strunz 2.C
Key characteristics
- Crystal system
- orthorhombic
- Mohs hardness
- 6–6.5
- Specific gravity
- 4.85–4.9
- Luster
- metallic
- Transparency
- opaque
- Color
- white, yellow, gray, brown
- Streak
- gray, black
- Cleavage
- distinct
- Fracture
- uneven
- Crystal habit
- tabular, prismatic, pyramidal, radiating, stalactitic, granular, massive
- Classic / historic
Buy Marcasite specimens
View all 70Where Marcasite is found
Top localities
- Ballard Mine13 specimens
- Ladywash Mine10 specimens
- Bou Nahas mine8 specimens
- Panasqueira Mines7 specimens
- Brushy Creek Mine6 specimens
- Buick Mine6 specimens
- Sweetwater Mine6 specimens
- Blackstone Mine5 specimens
- Buffalo5 specimens
- Cap Blanc-Nez4 specimens
Guides
All guides
Guide
Marcasite from Joplin Field, USA
Marcasite from Joplin Field — brassy, blade-like crystals often on galena in the Tri-State district, prized for sediment-hosted texture and striking contrast.Read guide
Guide
Marcasite from Cap Blanc-Nez, France
Cap Blanc-Nez, France — a premier locality for marcasite in chalk, prized for sharp bladed crystals and the key distinction from pyrite for collectors.Read guideAbout Marcasite
Notable specimens come from classic European locales as well as productive mines in the United States. In these settings marcasite often forms in hydrothermal veins and is frequently found with quartz, calcite, and siderite. While it can occur in oxidized zones, its stability is higher under reducing conditions where granular to compact masses and crystal clusters are preserved. The mineral’s commonly seen cabinet- to display-sized crystals, sometimes intergrown with pyrite, contribute to its frequent appearance in mineral cabinets and museum collections alike.
Collectors value marcasite for its historical significance and its ability to reveal intricate crystal forms. Its metallic luster and sharp edges can create striking contrasts when paired with contrasting host rocks. While not as rare as some sulfides, well-formed crystals from classic localities remain desirable for display and study among mineral enthusiasts.
