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Where to Find Marcasite in Missouri

Missouri marcasite is the orthorhombic cousin of pyrite, found in the same Mississippi Valley dolomite host rocks. The Tri-State chat piles around Joplin in Jasper and Newton counties yield bladed marcasite rosettes and cockscomb aggregates, often pseudomorphing after pyrite. The Viburnum Trend mines (Buick, Brushy Creek, Sweetwater) produce blocky marcasite on dolomite with galena and sphalerite associations. The Old Lead Belt around Bonne Terre adds tabular and stalactitic marcasite. Surface marcasite oxidizes quickly to a sulfuric film and crumbles within months, so specimens should be coated with a thin lacquer if displayed in humid environments.

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Every marcasite spot we track in Missouri

Best counties for marcasite in Missouri

Ranked by the number of mapped marcasite spots. County links open the full rockhounding page for that county.

Before you go

Read the marcasite identification guide so you know what a keeper looks like in the field: Marcasite in the encyclopedia.

Marcasite in Missouri FAQ

Where can you find marcasite in Missouri?+
The mapped spots concentrate in Crawford County, Boone County, and Franklin County. Known collecting areas include Joplin chat field (Jasper County), Buick mine (Iron County), and Old Lead Belt dumps (St. Francois County). Every spot on this page is on the map, and each spot's own page has its coordinates and access notes.
How many marcasite spots are mapped in Missouri?+
19 spots across 15 counties. The RockHoundR app keeps the same spots on an offline map with public land overlays, geology layers, and your saved finds.
Is it legal to collect marcasite in Missouri?+
Hand collecting of common rocks and minerals in small amounts for personal use is generally allowed on BLM and U.S. Forest Service land, with limits set by the local field office. National parks, most state parks, and tribal land are closed to collecting. 18 of the 19 mapped spots here sit on land marked public. Always confirm current rules with the managing agency before you dig.
How do you identify marcasite found in Missouri?+
Marcasite has the same brassy color as pyrite but is paler and cleaves into bladed plates. A fresh fracture shows tabular outline; pyrite breaks conchoidal.

Where else to find marcasite

More minerals to hunt in Missouri

Hunt marcasite in Missouri with the map in your pocket

RockHoundR puts these spots on an offline map with BLM and Forest Service overlays, geology layers, and a log for your finds.

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