PYRITE IN DOLOSTONE
Dolostone is a chemical sedimentary rock composed of dolomite (CaMg(CO3)2 - calcium magnesium carbonate). It is usually gray-colored, finely-crystalline, and often has irregularly-sized & irregularly-shaped holes called vugs. The dolostone shown below has a sucrosic (sugary) texture with abundant, relatively small vugs, plus beautiful, brassy-colored pyrite crystals that line part of a large vug (reportedly a ~2 foot-diameter subspherical cavity). Pyrite is iron sulfide (FeS2) and many of these crystals have colorful-iridescent oxidation films.
Stratigraphy & age: Lockport Dolostone (“Lockport Dolomite”), upper Niagaran Series (upper Wenlockian), upper Middle Silurian
Locality: sidewall of open-pit quarry, ~300’ below the surface, National Lime & Stone Company’s Buckland Quarry, just southwest of the town of Buckland, northern Moulton Township, northern Auglaize County, northwestern Ohio, USA.
Pyrite crystals on sucrosic dolostone (above & below) from the Lockport Dolostone at Buckland Quarry, northwestern Ohio, USA.