Diamonds are also noted for being the hardest natural material on the [[hardness|Moh's Scale]], and fairly rare (deposits are found in [[Kimberlite]] in [[South Africa]]). As such, natural diamonds are used for jewelry, and synthetic diamonds for drill bits. | Diamonds are also noted for being the hardest natural material on the [[hardness|Moh's Scale]], and fairly rare (deposits are found in [[Kimberlite]] in [[South Africa]]). As such, natural diamonds are used for jewelry, and synthetic diamonds for drill bits. |