As an outcome of a paper published by The University of Texas in 1938 calling attention to the high magnesia marbles of the Sharp Mountain area of Llano County, magnesite is mined at the present by two companies, the Meramec Minerals, Inc., and the Texas Mines. The Sharp Mountain area is a part of the metamorphic series, probably Algonkian in age, composed mainly of mica and graphitic schists, diorites, granite, dolomite, magnesite, magnesitic limestone, and calcium carbonate marble. The calcium carbonate marbles and dolomites, like other members of the series, are highly metamorphosed irregular bands and include such typical accessory minerals as tremolite, tourmaline, diopside, serpentine, talc, and wollastonite. The entire series has been intruded by granites, pegmatite, and aplite dikes. In part, this folded and tilted series is overlain by Cambrian and Ordovician strata where erosion has failed to remove it.