Clintonite

Clintonite is a mineral belonging to the brittle mica group. It is a trioctahedral phyllosilicate with the chemical formula Ca(Mg,Al)(Al,Si)3O10(OH)2. Clintonite is characterized by its platy, lamellar habit and often occurs in massive or granular aggregates. It is typically found in metamorphosed limestones and marbles, particularly those that have undergone contact metamorphism. The color of clintonite can vary, commonly appearing as shades of yellow, reddish-brown, or greenish. It has a vitreous to pearly luster and a Mohs hardness of 5.5 to 6.5. Clintonite is notable for its relatively high calcium content. It is named after DeWitt Clinton, a former Governor of New York, in whose honor the mineral was first described. Notable occurrences of clintonite include localities in the United States, such as the Sterling Hill Mine in New Jersey, and various sites in Canada and Europe. While not economically significant, clintonite is of interest to mineralogists for its place within the complex mica group and its association with specific metamorphic environments.