GMS represents five different quarries, and sells stone as finished slabs and tiles, which are processed in Custonaci. The company also offers architectural pieces such as window sills, steps and other items.

The quarries in Custonaci include sites for Perlato di Sicilia classifications as well as Perlatino. It has also started a new quarry for Libeccio marble near the Perlato and Perlatino quarries. This material, which was used in the Vatican, has been specified for an exclusive hotel in Dubai, United Arab Emirates. Additionally, it is already being sold in the U.S. marketplace.