: This makes it the "gold standard" for jewelry intended for daily use, such as engagement rings.
: Its toughness allows it to be used in heavy-duty abrasives (like sandpaper and grinding wheels), scratch-resistant watch crystals, and even windows for spacecraft and satellites. Prominent Varieties of Corundum corundom
: As the second hardest natural mineral, it is highly resistant to scratches and abrasions from almost any other material. : This makes it the "gold standard" for