Corundum has many other uses. It is chemically inert and resistant to heat. These properties make it a perfect material for making refractory products such as fire brick, kiln liners, and kiln furniture. Today, these products are usually made with synthetic corundum.

Pure corundum is colorless, transparent, durable, and scratch resistant. Large crystals of clear synthetic corundum are grown, sawn into thin sheets, and then used as the windows of grocery store scanners, watch crystals, aircraft windows, and protective covers for electronic devices.