Corundum Tumbled Stones
Corundum has two primary gem varieties: ruby and sapphire. Rubies are red due to the presence of chromium, and sapphires exhibit a range of colors depending on what transition metal is present.
Pure Corundum is one of the hardest stones on earth, trailing only Diamonds on the Mohs scale. That means that Corundum can scratch almost any other minerals. That makes this stone a prime candidate for use as sandpaper, some emery and many large tools used in machining metals, plastics and woods.
Corundum typically occurs as a mineral in mica schist, gneiss, and some marbles in metamorphic terranes. The largest documented single crystal of corundum measured approximately 26 in × 16 in × 16 in and weighed 335 pounds.
You will receive one stone, which has a size/shape that may vary due to each stone being unique in color and form. Most stones range between 0.6"-1.2"