Martin Marietta Materials 

Martin Marietta Materials is one of the United States' largest producer of construction aggregates (crushed stone, sand, and gravel). Martin Marietta's most important markets include Texas, North Carolina, Colorado, California, and Georgia, accounting for most of its sales. The company also uses its aggregates in its asphalt and ready-mixed concrete businesses. Martin's magnesia specialties business produces magnesia-based chemical products and dolomitic lime.