Carbonate Minerals

Carbonate minerals (CO₃) are common where sedimentary rocks dominate. The Ohio Valley is one such area, including Indiana, Kentucky, and Ohio. The purpose of this page is not to explain the science of carbonate minerals – there are many websites with that objective. This page serves to illustrate carbonate minerals so that you can see what has been found.

Smithsonite – Zinc Carbonate – is uncommon in the Ohio Valley, but is found where sphalerite (zinc sulfide) has weathered in the earth. It is a minor ore of zinc occurring in small deposits like the Old Jim and Columbia mines in Crittenden Co., KY, and the Hutson mine in Livingston Co., KY. See the page on the Illinois-Kentucky fluorspar district for more information.

Smithsonite coating barite from the Walker vein, Central Kentucky Mineral District, Danville, Boyle Co., KY.

Details in the photo above. Smithsonite forms a crust. FOV 3.5 cm

A microphoto of cadmium-colored smithsonite crystals on an Ordovician bryozoan. From the Danville Quarry. FOV ~5mm

Smithsonite in bowtie-shaped crystals on barite. Danville, KY. FOV ~2.5 cm

Greenockite (CdS) colors smithsonite, giving it a yellow hue. On smithsonite. From the quarry in Danville, KY. FOV ~3 cm

Strontianite – Strontium Carbonate – is an uncommon mineral in this region, formed from weathering of celestine (strontium sulfate). Strontianite forms tiny, curved crystals, most often in small “puffball” shapes. Fine specimens are known from the fluorspar district and locations, like the Faylor-Middle Creek Quarry near Winfield, Pennsylvania.

Strontianite fuzzballs on barite, from the Walker vein, Caldwell Stone Co. Quarry in Danville, Boyle Co., KY. FOV ~2.5 cm

Pennsylvania Strontianite

A classic strontianite from the Faylor-Middle Creek Quarry, Winfield, PA. Ex-Steve Garza specimen.