Ruby and sapphire specimens. Crystals of ruby, the red variety of corundum (aluminium oxide). The other gemstones present here (blue-white) are sapphires. The rubies are from Burma. The sapphires are from Kashmir. The large ruby at lower left is the Edwardes Ruby (167 carats). This is named for Major General Sir Herbert Benjamin Edwardes (1819-1868). It was donated by John Ruskin to the Natural History Museum in 1887.