DIOPTASE -Dioptase was first found in the late 18th Century. Copper miners discovered it and thought they’d found the emerald deposit of their dreams, however, when tested it was discovered that it is not as hard as emeralds -Dioptase is used as a pigment for paint.
DIAMOND -Diamonds are the hardest natural substance on earth. -Light normally travels at 186,000 miles per second, but diamond is so dense that it slows light to less than half that speed. -You can pay to have your cremated ashes made into a diamond.