Along with the emerald and sapphire, ruby is one of the most prized coloured gem available. The main quality of the ruby is its bright red colour. The best colour usually comes from Burma and is very costly; stones from Thailand are darker but clearer and much more common. Only red stones are called rubies. If the colour is too light to be called red, it is a pink sapphire.

Corundum, the main material of ruby, is the second-hardest material known after diamond. Inclusions and flaws are fairly common, and many rubies are treated to enhance their colour. In general, one should look for a bright red stone with as few inclusions as possible. Synthetic rubies offer good colour, clarity and size, and are more affordable.

Rubies were the most valuable gems in ancient Southeast Asia, where they are found. A fine ruby had all sorts of magical powers. Its colour was thought to come from an undying flame inside the stone – or, in some legends, a piece of the planet Mars – and it allowed its owner to live in safety, even in the midst of enemies. It was believed to bring its owner all kinds of protection and to stop bleeding. In Burma, it could make one invincible – as long as it was embedded in the skin. In more modern times, rubies became the symbol of love and passion.

Ruby is July’s birthstone.

Colour Description
Various shades of red Corundum (aluminum oxide), the same family as sapphire, with the colour coming from chromium. Mohs hardness rating of 9.