Ruby is the red variety of the mineral Corundum, of which sapphire is also a variety, and is one of the four precious stones. Only red corundum can be called ruby.
Ruby is an aluminium oxide with traces of chromium, which creates the red colour. The range of reds varies with the individual deposits and locations. Traces of iron will create a more browny red. The most desirable colour is ‘pigeon’s blood’ - pure red with a hint of blue.
As a rough stone, ruby appears dull, but when cut, the lustre can be almost as good as diamond. Inclusions in rubies are common. An inclusion of rutile needles, for example, can produce a sheen, called silk. If the stone is then cut into a cabochon, a cat’s eye effect, or asterism, can be apparent moving over the surface when the stone is moved or rotated. Ruby scores 9 on Mohs’ scale, the most durable gemstone after diamond.
Rubies are found in crystalline limestone rocks or alluvial pebbles derived from the rocks. Some of the finest rubies, with the unique ‘pigeon’s blood’ colour have been mined in Myanmar (Burma), in the Mogok Valley, although in recent years the supply has diminished considerably. Rubies are also found in Sri Lanka, Thailand, Tanzania, Kenya, Madagascar, Cambodia and in the USA in Montana and North and South Carolina.
HISTORY & MYTHOLOGY
The name ‘Ruby’ comes from the Latin word ‘ruber’ meaning red. Rubies have been mined for about 2,500 years and have been prized throughout history. It is one of the most valued gemstones.
Ancient Hindus believed that the red colour of ruby came from an internal flame that could not be put out, making the stone a symbol of everlasting love. According to Sanskrit writings, the Hindus called rubies ‘ Ratnaraj’, ‘the King of Gems’.
Biblical references to ruby (all red gemstones were called carbuncle at this time) also call it the most precious of stones. Native Americans believed that an offering of a fine ruby would ensure rebirth as a powerful emperor. Some cultures believed that ruby could project the wearer from any injury, due to its blood-like colour. Ancient Burmese warriors would insert a ruby beneath the skin so that no one could conquer them in battle. In the Middle Ages, people believed that rubies contained the power of prophecy, and would darken in colour to warn it’s wearer of impending danger, then lighten again, once the peril had disappeared.
Ruby is the birthstone for the month of July and the Cancer sign of the zodiac (June 21st to July 22nd). It is also given as an anniversary present to celebrate 15 and 40 years of marriage.