Perhaps no gemstone has been as prized throughout history as the ruby. Celebrated in ancient Sanskrit writings as the most precious of all gemstones, rubies have adorned emperors and kings and inspired countless legends and myths with their rich, fiery hues.
As the ultimate red gemstone, rubies have symbolized passion and romance for centuries. Ruby is the birthstone for July and is also the recommended gem for couples celebrating their 15th and 40th wedding anniversaries.
Also the color of blood, the stone is symbolic of courage and bravery. Warriors were said to have implanted rubies under their skin to bring them valor in battle and make them invincible. The stone has also been used as a talisman against danger, disaster, to stop bleeding, and a number of other ailments. Its intense color was thought to come from an undying flame inside the stone - or, as some legends would have it, a piece of the planet Mars.Ruby is the red variety of corundum, a sister of sapphire. Like sapphire, ruby rates a "9" on the Mohs scale of hardness, making it the second hardest material known after diamonds.
The most important factor to consider when buying a ruby is its color. It comes in a variety of shades ranging from purplish- and bluish-red to orange-red. Like sapphire, there is also a translucent variety of ruby that can display a six-point star when cut in a smooth domed cabochon cut.
Rubies are rarely found perfect in nature - which is why many are heat-treated to intensify or lighten their color or improve their clarity. Heat enhancement is a permanent, stable process. Some rubies also have surface fractures and cavities that are filled with glass-like materials to improve their appearance.
For both treated or untreated stones, the safest cleaning method is to just use soapy water or a mild commercial solvent and a brush.