Phosphates are minerals that are combined with phosphorus and oxygen. Apatite is common in various places in Kentucky.
Crystal system: hexagonal. Fracture: conchoidal. Color: red, brown, white. Hardness: 5.0. Luster: opaque or semitransparent. Specific gravity: 3.1.
Apatite, also called collophane, occurs in peridotites in eastern and western Kentucky. A microcrystalline variety of collophane found in central Kentucky is dark reddish brown, porous, and occurs in phosphatic beds, lenses, and nodules in the Tanglewood Member of the Lexington Limestone in northern Woodford County. Some fossils in the Tanglewood Member are coated with phosphate. Beds are generally very thin, but occasionally several feet thick. The Woodford County phosphate beds were mined during the early 1900's.
Crystal system: monoclinic. Color: blue. Hardness: 2. Specific gravity: 2.68. Vivianite commonly occurs in radiating small aggregates or earthy masses. It is rare, though () reported in Floyd County. It is possible that this mineral could occur in geodes, nodules, or fossil cavities in the phosphate beds of central Kentucky.
Crystal system: hexagonal. Cleavage: occurs in rounded or barrel-shaped crystals. Color: light green to brown. Hardness: 4. Specific gravity: 7.0.
Pyromorphite is a rare lead phosphate that can occur in oxidized lead deposits and has been reported at the Big Four Mines and Dike Eaton areas in the Western Kentucky Fluorspar District.