Corundum is one of the hardest minerals at a 9 on the Mohs Hardness scale. This mineral is found worldwide in igneous and metamorphic rocks. Common samples of corundum are gray to black in color; however, the red and blue varieties of corundum are the gemstones ruby and sapphire, respectively.
An information card with details on the mineral formation, characteristics, and uses is included. Typical samples sizes are generally 1-2 inches in length or width but can vary based on availability and natural crystal shape.
WARNING: CHOKING HAZARD-Small Parts. Not for children under 3 years.
May have sharp edges.