Diamond

Diamond, elemental carbon, is the strongest mineral on Earth, four times harder than second-hardest mineral, corundum (saphire and ruby). It defines the top of the Moh’s hardness scale, and has the highest melting point of all minerals. Diamond’s color is variable, tending towards pale yellows, browns, grays, and also white, black, reddish, greenish, or colorless. Diamond is the birthstone for the month of April.