Corundum is a naturally occurring mineral made of aluminum oxide. It is known for its hardness, ranking just below diamond on the Mohs scale, which makes it an excellent material for abrasives. Corundum can be found in various colors, including clear, red, blue, and yellow, depending on the presence of trace elements. The red variety is known as ruby, while the blue variety is called sapphire. This mineral is commonly used in jewelry due to its beauty and durability. Beyond adornment, corundum is also utilized in industrial applications, such as sandpaper and cutting tools, thanks to its exceptional strength. Its versatility makes it an important material in both decorative and practical uses.