History of Ruby
Ruby, whose name is derived from the Latin ‘ruber,’ meaning red, is the birthstone for July. Ruby’s intense crimson colours have mystified, entranced and romanced since it was first found over 2,500 years ago. Sri Lankan Rubies may have been available to the Greeks and Romans as early as 480 BC. Ruby was once known to the ancient Indians as 'ratnaraj', the king of gems, they believed Rubies could endow a long life.
Burma Ruby is the rarest and most valuable member of the corundum family. Colors range from pink red ruby to a vivid pigeon blood red that is regarded as the finest color for ruby.
Prized for their beauty, durability, and rarity, it is the quality of the color which most determines the value of rubies. The pigeon blood red color is that of a red traffic light, a fluorescent red of high intensity. Demand for gem quality Burma Ruby has always been strong with mining records from Burma dating back almost 500 years. Officially, ruby, jade, and other gems are Burma’s (Myanmar's) fifth-largest export, but government statistics are notoriously unreliable. Official ruby gem and jade sales are sold at Myanmar’s gem auctions, but hundreds of millions of dollars worth of gems leak across borders to China, Thailand, and India every year, selling at open market prices.
Burmese Rubies are considered the best, for one simple reason - their color. The most famous localities for Burma Rubies are in the districts around Mogok in northern Burma and at Mong Hsu about 250km east of Mandalay. Rubies tend to have significant i so eye clean specimens are rare.
The classic rubies from Mogok characteristically contain short, fine, rutile needles -- so-called silk. These dust-like inclusions occur either as overall cloudiness, in patches, or in distinct zonings. Generally, long slender rutile needles in reticulated patterns are more common in pinkish red rubies. Boehmite needles are restricted to twin planes and other lamella in ruby.
The other most common inclusions in Mogok rubies include colorless calcite and dolomite (sometimes yellowish)-both manifest internal twinning and/or cleave planes- prismatic apatite, feldspar, pyrrhotite, titanite, magnetite, micas, spinel, and possibly tourmaline, diopside and many other minerals. Fluid inclusions on healed fractures (healing feathers) are also typical features in Mogok rubies. Negative crystals of mixed solid and fluid are not uncommon.
Mogok rubies are known for their intense "pigeon-blood" color, enhanced by daylight fluorescence, but saturation ranges to pink. Pronounced crystallographic color zoning is rare, but subtle banding and small "swirls" of color zoning, known as treacle, are common.
Mogok-1: A combination of subhedral and irregular carbonate (calcite?) inclusions are in the center of the image; middle left inclusion shows rhombohedral cleavage. A patch of fine silk to right and fine fluid inclusions on a healed feather. [Frame is 3 mm wide.]
Mogok-2: Same stone as Mogok-1. The central inclusion shows several cleavage plains, indicating it is probably calcite. [Frame is 3 mm wide.]
Mogok-3: Several inclusions showing negative crystal form; perhaps mixed carbonate & fluid. Large ruptured/fractured mixed inclusions below and out-of-focus feather above. [Frame is 3 mm wide.]
Mogok-4: Fine oriented needles of rutile merge into denser silk to left. [Frame is 3 mm wide.]
Mogok-5: Three orientations of rutile needles (therefore, looking down c-axis) with one set forming bands of characteristic silk. [Frame is 3 mm wide.]
Properties of Ruby
Tanzanian Ruby, also know as Songea Ruby, is from a deposit just outside the town of Songea in Tanzania that was only discovered in 1992.
When it comes to Ruby, the intensity and purity of its signature reds are where the value lies. Ruby's 'pure' reds seldom exist, as it is a diochroic (two-coloured) gemstone. Even the 'finest' Ruby will still only be around 80 percent pure red, with secondary splashes of orange, pink, purple and violet. While a gemstone's colours should ideally remain beautiful in any light source, Rubies usually look their best when viewed outdoors in natural light or under incandescent lights.
While both Ruby and Sapphires are classed as Type II gemstones (gems that typically grow with some minor inclusions in nature that may be eye-visible), Rubies are usually more included and smaller. While an eye-clean clarity is desirable, just remember that perfection in nature is a scarce commodity indeed; an eye-clean Ruby is extremely rare.
Rubies are available in a huge array of shapes and cuts with ovals being the most common. It is also cut 'en cabochon', not only for its star varieties, but also for examples whose clarity makes them unsuitable for faceting.
Due to an optical special effect called 'asterisk' or the 'star effect', parallel needle-like inclusions create a reflected luminous star of light that moves across the gemstone. For Corundum, reflections from a whole host of tiny rutile needle inclusions, also known as silk, cause their stars. A unique and rare gemological phenomenon, Star Rubies were sometimes known as 'the three swords' in Europe, due to their alleged ability to banish evil, bring good luck and help find a good spouse. All star gems are dependent on a gem being cut 'en cabochon' (cut in convex form and highly polished, but not faceted). While asterisk is most visible in a direct, single beam of light, a well-cut star gemstone has a distinct star whose rays are straight and equidistant. The norm is a six-rayed star, but 12-rayed stars also occasionally occur. In Star Ruby, the distinctiveness, intensity and transparency of the red body color are also important value considerations. While the gem gravels of Sri Lanka are the world's 'classic' source, having supplied this gemstone for over 2,000 years, other modern sources include Burma, India, Madagascar and Mozambique.
Source of Ruby
Sri Lanka may be the oldest source, the 'classic' origin for Ruby is the Mogok Valley in north-central Burma. Today, Ruby is also mined at Möng Hsu in Burma's northeast. Burma is still regarded as the world's finest source because of its Ruby's classic colours and transparency. Other sources for Ruby include Afghanistan, Cambodia, China, India, Kenya, Madagascar, Mozambique, Pakistan, Sri Lanka, Tanzania, Thailand and Vietnam.