Search Results for: Kephir not concentrated
sapphires and rubies of highest quality, color, and clarity are formed in marble along the edges of subsurface magma bodies. corundum's toughness, high hardness, and chemical resistance enable it to persist in sediments long after other minerals have been destroyed. this is why it is often found concentrated
and powders. these are used for grinding media, polishing compounds, sand papers, grinding wheels, and other cutting applications. some problems with using natural corundum as an abrasive are that the deposits are usually small, irregular in shape, and the corundum is of variable quality. they are not...
https://geology.com/minerals/corundum.shtml