Calcite

Unknown Owner

Wonderful large cluster of translucent lustrous scalenohedral calcite crystals without matrix. This is in terrific condition. Excellent for the species and locality.The Hanson Quarry, historically known as the Medusa Quarry or the France Stone Quarry, is located in Sylvania, Lucas County, Ohio, and is a premier Midwestern locality for both fossils and minerals. Geologically, the quarry exposes a sequence of Middle Devonian sedimentary rocks, including the silica-rich Silica Shale and the overlying Dundee Limestone. Within the vugs and fractures of these carbonate rocks, hydrothermal fluids precipitated aesthetic crystals of celestine, calcite, and pyrite, with the celestine typically appearing as colorless to pale blue tabular crystals. Historically, the site began as a commercial operation for crushed stone and cement raw materials in the early 20th century and has been operated by various entities, including the Medusa Portland Cement Company and later Hanson Aggregates. The quarry gained international fame in the mid-20th century, particularly during the 1950s through the 1980s, for producing world-class trilobite fossils and fine mineral specimens. While active industrial mining continues to provide aggregate for the construction industry, the quarry remains a classic reference site for the mineralogy and paleontology of the Michigan Basin.