Onyx

Onyx is a variety of chalcedony, a cryptocrystalline form of quartz, prized for its intense, deep black color. While not a mineral itself, its deep black hue makes it a popular gemstone for jewelry and decorative objects. Significant sources of black Onyx include India, Brazil, Uruguay, and the United States (Arizona, Nevada, and California). Other countries in Africa and the Middle East also produce Onyx, but the quality and color can vary.