Black Onyx Ring, size 8
The ancient Romans entered battle carrying amulets of onyx engraved with Mars, the god of war. This was believed to bestow courage in battle. In Renaissance Europe, wearing onyx was believed to bestow eloquence. A traditional Persian belief is that it helped with epilepsy. Onyx was traditionally used by English midwives to ease childbirth by laying it between the breasts of the mother.
Onyx is an ancient gemstone, having been used in jewelry and as an ornamental gemstone for carvings since antiquity. Onyx has traditionally been one of the most important engraving and cameo gemstones, where its most common form was a black base with a white upper layer. Although still used a minor gemstone today, the significance and value of Onyx has been diminished as compared to ancient times.
When Onyx is banded black and white, it can be jointly classified as both Agate and Onyx. However, many require Onyx to have banding in roughly parallel lines, whereas other forms of Agate can have wavy or concentric forms of banding.