Corundum

Corundum is a mineral that occurs in various colors, including red (ruby) and blue (sapphire). It is one of the hardest minerals and is often used as an abrasive and in jewelry making. Corundum has high resistance to abrasion and chemicals and is also used in industrial applications due to its hardness. In addition to its practical uses, corundum is also valued as a gemstone due to its attractive colors and transparency. Ruby and sapphire, which are both forms of corundum, have a long history as sought-after gemstones. Their vibrant colors and hardness make them popular choices for high quality jewelry.