September’s birthstone has come a long way since the days when any and every blue stone was called a sapphire. Though its fame is shared with its “Big Three” counterparts ruby and emerald, sapphire has enjoyed a long run as one of the world’s most beloved gemstones, earning itself a place of honor in crown jewels, royal accessories, museums, and even in modern royal engagement rings. Lest sapphire get too haughty, it has common uses as well. The rough polishing material on emery boards is made up of lower-quality corundum grains, strengthened with hematite, magnetite and quartz.