Essential notes on precious stones
Ruby, July's birthstone, is named the King of Gems. Both the Bible and ancient Sanskrit writing depict the ruby as the most precious of all gemstones. To the Hindus, Ruby burned from an inextinguishable internal fire.
Sister to Sapphire, Ruby is known in the mineral world as corundum, which is a crystal structure composed of aluminum oxide. Only red corundum is Ruby, its color being given by small contents of chromic oxide, all other corundum colors are classified as Sapphire. Ruby is considered the most valuable variety of the corundum. On the Mohs scale of hardness, Ruby ranks 9, sharing status with Sapphire as the highest in the gem world after Diamond. It is considered very durable, a great choice for rings and bracelets that are prone to knocks.
The most famous source for natural gem-quality ruby is Myanmar (Burma). Good stones have also come from Thailand, Sri Lanka, and most recently, Vietnam. However, Myanmar remains the largest and best source for Rubies of top-quality, free of inclusions and a dark-pink red color that holds its glow in all lighting conditions. Rubies are also mined in Africa, Afghanistan, and Central Asia, but these mines have yet to yield a significant source of good rough stones. The center of the Ruby trade is in Thailand, in Chantaburi as well as near the Myanmar border, as close as one can get to the mines without being under the totalitarian Myanmar military government. Many of the best Ruby cutting and polishing traditions are in the Thailand, and much of the international trade of finished stones takes place in Bangkok.
Perfect natural rubies in color and appearance are very rare and expensive, even more rare than sapphires, as chrome is rarer than steel in nature too. Controlled heating is commonly used in the trade to produce, intensify or lighten color and/or improve clarity. This allows the trade to bring more, better quality gems to the market. Heat enhancement is permanent and stable.
Some Rubies have fissures that break the surface and are filled with a glass-like byproduct from the heating process. Surface cavities in rubies are also intentionally filled with such material as glass, solidified borax or similar colorless substances to improve its durability and appearance.
It is important to buy fine Ruby from a reputable jeweler retailer who will provide all pertinent information regarding the gems.
The name Ruby is derived from the Latin word for red, rubrum.
Its color varies from purplish and bluish red to orange-red in medium to dark hues. In fact, large Rubies have consistently brought higher prices per carat at auctions than the most flawless, colorless Diamonds! This is primarily due to the rarity of gem-quality rough Ruby.