Colorful CHALCEDONY is a type of AGATE, a semi-precious stone that is formed from quartz. It is known for its vibrant colors and intricate patterns, which are created by the presence of other minerals in the stone. Agates can be found in many different colors, including red, blue, green, yellow, and purple. The term 'CHALCEDONY' is derived from the Greek word for 'BRONZE, ' which is indicative of the stone's metallic sheen.