corundum

Corundum is a mineral composed mainly of aluminum oxide, known for its hardness and durability. It naturally forms in hexagonal crystals and can appear in various colors depending on trace elements—such as blue for sapphires and red for rubies. Corundum ranks 9 on the Mohs scale of hardness, making it one of the toughest minerals, ideal for industrial applications like abrasive materials and cutting tools. Its striking appearance and strength also make it highly valued as a gemstone, symbolizing qualities like wisdom and integrity.