Ruby

History
Ruby is quite possibly the world's oldest known gemstone. The oldest ruby mines in the world are near Mogok in Burma, now Myanmar, and contain tools dating as far back as the stone age. Ancient Romans named the stone "ruber" which means "red" in Latin, and Marco Polo's thirteenth century writings tell of an ancient Burmese legend of great antiquity, in which rubies figure prominently.

Features
Ruby crystals are generally six-sided and often flattened or barrel shaped. As part of the corundum family, they are among the hardest gemstones in the world, next to diamond. Rubies can range in color from a deep purplish red to a bright pinkish red, and are often included with other crystals, minute amounts of liquid, called feathers, or "silk" made of fine rutile needles. Rubies can also contain surface-reaching fine cracks, but generally, the more transparent the stone, the finer the quality. Rubies also are available as star stones.

Treatments
Because of ruby's nature to contain surface-reaching cracks, they are routinely oiled with a red colored cedar oil or similar oil. This gives treated stones the appearance of greater transparency, and therefore greater value. Often rubies which are darker than the "ideal" bright red color are heated to drive off the purplish tone. Cloudy or opaque stones are often heated and then cooled slowly to dissolve the rutile silk inside.

Principal Deposits
The Mogok region in Myanmar, both historically and in modern times, contain the world's most abundant source of ruby. Other locations include India, Pakistan, Sri Lanka, Thailand, China, and many other countries.

Rarity
As with diamond, a perfectly clear, rich red ruby is a very rare and valuable thing. However, since ruby comes in a range of color and clarity, decent quality stones can be found for a range of tastes. In the case of star ruby, the odds of discovering a well formed star in a rich red stone are less than one in ten million.