5.4" Sphalerite Cluster on Sparkling Dolomite - Elmwood Mine

The Elmwood Mine

The Elmwood Mine in central Tennessee is one of the world’s premier localities for fluorite, barite, and sphalerite, producing specimens renowned for their size, color, and exceptional crystal quality. Forming within Mississippi Valley–Type (MVT) deposits, Elmwood fluorite is famous for its rich grape-purple cubes—often water-clear and stepped—with barite perched elegantly on top in creamy clusters or golden blades. The mine’s sphalerite is equally celebrated, yielding lustrous, gemmy crystals ranging from fiery orange to deep red-black. Together, these species make Elmwood one of the most iconic and collectible mineral localities on the planet, known for generating museum-grade combinations unmatched in aesthetics and mineralogical significance.

Commercial mining at Elmwood began in the late 1960s, when the site was developed as part of the larger Central Tennessee zinc district. For decades, the mine operated primarily as a major source of high-grade zinc ore for industrial use, with fluorite, barite, and collector-quality sphalerite crystals forming as spectacular but incidental byproducts of the ore-extraction process. Periodic closures and reopenings—driven by fluctuating zinc prices and ownership changes—have made fine Elmwood specimens increasingly coveted over time. Although the mine’s primary purpose was always zinc production, its unexpected yield of world-class mineral specimens has cemented Elmwood’s place as one of the most important and beloved mineral localities in North America.

Sphalerite is a part of the sulfide group and typically exhibits a grey/black appearance due to high concentrations of impurities. In its purest state, sphalerite's chemical composition is ZnS, and can display a gemmy transparent light tan/yellow color. This is one of the few minerals that can form crystals ranging anywhere between gemmy and transparent to opaque and metallic-like. Opaque or cloudy sphalerite tends to be most abundant since iron easily replaces zinc in the process of formation.

Dolomite is an anhydrous carbonate mineral composed of calcium magnesium carbonate (CaMg(CO3)2).

The mineral dolomite crystallizes in the trigonal-rhombohedral system. It forms white, tan, gray, or pink crystals. Dolomite is a double carbonate, having an alternating structural arrangement of calcium and magnesium ions. It does not rapidly dissolve in dilute hydrochloric acid as calcite does. Crystal twinning is common.

Dolomite was first described by Carl Linnaeus in 1768, and in 1791 it was described as a rock by the French naturalist and geologist Déodat Gratet de Dolomieu. He first recognized the material in buildings of the old city of Rome, and later as samples collected in the mountains known as the Dolomite Alps of northern Italy.