Onyx is commonly mistaken for agate and vice versa. They are almost identical except for the main difference which states agate has curved bans while onyx has parallel bands. Onyx is found in many different colors ranging from white and black to brighter reds and yellows. Onyx has a been used in jewelry and trinkets for many centuries. Common uses in ancient times include beads and even bowls and plates. Black Onyx is commonly associated with the root chakra.