Minerals

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Name:	Corundum - Ruby and Sapphire
Derivation:	From "kurundum" (Tamil) From "rubeus" (Latin) red From "sappheiros" (Greek) lapis lazuli
Formula:	Al₂O₃
Description:	Very hard crystal. Red corundum is ruby (left). Blue curundum is sapphire (right). Or you can just have corundum (below right).

Corundum is a very hard stone. Another name of Corundum is Emery, and Emery paper is used for rubbing things smooth.

Sapphire was originally the name of lapis lazuli. The name of sapphire was Hyacinthus, because they were supposed to look like the flower. Now Hyacinthus is another name of zircon (which looks nothing like sapphire!) Romans used Sapphires for the development of greater trade with India at the time of the Emperor Trajan.

Ruby was used for different types of red stones. It was fixed as Red Corundum in about 1800. In the Bible (King James' version), in Proverbs, it says "Who can find a virtuous woman? For her price is far above Rubies." However, it is now thought that Coral was meant by this. You can see from this, and the muddle over Sapphire's name, that there has been great confusion over the names of stones throughout history.

Good quality rubies are still very valuable, as much or more than diamonds. The "perfect ruby" is an alchemist term for the Elixir or Philosopher's Stone, which would turn ordinary metal to gold, and would make you live for ever. (No-one ever found it! But alchemists learn a lot about chemicals while trying, and provided a foundation for modern chemistry). Some rubies can be cut so there are pale streaks coming from a point. These are called star rubies.