The name CORUNDUM is derive from Tamil word KURUNTUM meaning ruby, Corundum is Crystalline from of aluminum oxide (Al20),Synthetic Corundum is best substitute for Natural Ruby and Blue Sapphires,
Synthetic Corundum hardness is 8.5 -9.0 in mohs scale, with high melting point of 2050 C, it is fully suitable for wax casting process.