A member of the S&P 500 Index, Martin Marietta is an American-based company and a leading supplier of building materials - including aggregates, cement, ready mixed concrete and asphalt. Through a network of operations spanning 30 states, Canada and the Bahamas, dedicated Martin Marietta teams supply the resources necessary for building the solid foundations on which our communities thrive. Martin Marietta's Magnesia Specialties business produces high-purity magnesia and dolomitic lime products used worldwide in environmental, industrial, agricultural and specialty applications.