Chrome Ore sand, Originally from South Africa ,is a special kind of sand for casting ,

Chrome Ore sand is a natural spinel mainly composed of chromite ,Chrome Ore sand used as a highly fireproof sharpener for moulds and cores.

Chromite Sand in the glass industry

When ground to a fine flour, Chromite Sand is used for the production of green glass beverage containers

Chromite Sand in the foundry industry
Its properties enable the material to be used in high duty grey iron and steel foundries as core and mould making sand. 
Chromite Sand in the steel industry
In steel production, Chromite Sand is used as well filler for protection of the sliding gate in large steel holding ladles.