Description: Striped brown and white chalcedony.
If you have an onyx with brown and white stripes, then it becomes a sardonyx. These can be cut in several ways. You can have a cameo, a slice through (which is sometimes called a banded agate), or, most striking of all, you can cut it so it looks rather like an eye. These were used by Sumerians, Egyptians, Greeks and Romans to ward off evil.