Smythite in Calcite with Dolomite

specimen number:
2063742

location:
Bloomington Crushed Stone Co. Quarry, Monroe Co., Indiana, USA

description:
A grouping of colorless mostly gemmy lustrous scalenohedral calcite crystals measuring to 3.5 cm in height, these coming off matrix with light pink crystallized dolomite. Richly included throughout these calcite crystals are small metallic micro crystals of smythite. This is in good condition. The specimen comes with a previous label from the collection of Ray DeMark. He acquired the piece from Jerry Ostrom who collected the specimen in 1960.

The Bloomington Crushed Stone Company Quarry in Monroe County, Indiana, is an active limestone operation famous in mineralogy as the type locality for the rare iron sulfide mineral smythite. Operating within the Mississippian Harrodsburg Limestone and Salem Limestone formations, the quarry uncovers geode-bearing zones and mineralized fractures formed by low-temperature hydrothermal solutions. Discovered at this quarry in 1956 by mineralogists Richard Erd and Charles Milton, smythite occurs as minute, highly lustrous, dark bronze to black platy micro-crystals and thin hexagonal flakes embedded within calcite, barite, quartz, and pyrrhotite matrix. Collectors and researchers value the locality because smythite is an unstable, magnetic iron sulfide phase that rarely forms macroscopic crystals elsewhere, making specimens from Bloomington essential reference material for classic North American mineral collections.

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