The birthstone for September is none other than sapphire, known for its rich color and gorgeous glimmer. As crystal expert and co-founder of Energy Muse Heather Askinosie explains to mbg, sapphires are part of the corundum variety of gems. They have a hexagonal crystal structure and are very, very hard. Sapphires are primarily sourced from India, Sri Lanka, the state of Montana, Western Africa, and Australia, she adds.