Namibia

Also known as Black Tourmaline, Schorl is rich in iron and forms in a wide variety of rock types all around the world. While it's not a common gemstone for jewelry, it has found a place historically in Victorian mourning jewelry. One of the more famous pieces of Black Tourmaline mourning jewelry is in honor of Alexander Hamilton for his widow, Eliza Schuyler Hamilton. This ring is still kept by a Hamilton descendant. 

Namibia is known as one of the world's most famous deposits of Black Tourmaline.