BURMESE RUBY

Myanmar (formerly known as Burma) is world famous for Burmese Rubies (sometimes used as a trade term for finest quality rubies, and not always indicative of geographical origin). A historical producer of fine quality rubies to this day, characteristics typical of these stones include any combination of:

Silk (rutile needles) and other clarity characteristics that diffuses light in the stone.

Red fluorescence that further adds to their crimson color in daylight (caused by high chromium).

Note that that iron inhibits fluorescence in rubies.

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 inclusions, so eye clean specimens are rare.

The prices and value of Burma Ruby can vary tremendously, depending on the size and quality of the gemstone.  AJS Gems is one of the leading dealers in high quality Burmese Ruby and we supply collectors and jewelers around the world.

Origin;    Burma (Myanmar)
Color;     red, blood red, vivid red, pigeon blood red, pinkish red, orangey red,                             purplish red
Refractive Index;               1.759-1.778
Chemical Composition;   AL2O3
Hardness;             9
Density; 4
Crystal Structure;              Trigonal
Zodiac Sign;          Leo
Planet;   Sun
Month;  July
Anniversary;        5th and 45^th

Sapphire and Ruby are both corundum, Sapphire is used for all colors of corundum except for red. Red corundum is called ruby. Pure corundum is colorless, and the various colors are result from trace elements. For example, blue sapphire results from a combination of titanium and iron oxides. Sapphire colors include blue, pink, yellow, green, purple, orange, padparadscha, blue green, lemon yellow, color change, and black.   With a hardness of 9 on the Moh's scale, sapphires and rubies are extremely hard and durable, and are suitable for use in any kind of jewelry.

Most gems have a crystalline structure. Crystals have planes of symmetry and are divided into seven symmetry systems. The number of axes, their length, and their angle to each other determine the system to which a crystal belongs.  Ruby and Sapphire have the same trigonal crystalline structure because they have three planes of symmetry and four axes. Three axes are at 60 degrees to each other in the same plane. The fourth axis is perpendicular and unequal in length to the other three. The form of a ruby's crystals depends on the variety and locality. Rubies may have an uneven or a conchoidal fracture but no real cleavage. The amount of light reflected at the surface of a gemstone is its luster, and Burma rubies have a glassy (vitreous) luster as opposed to the waxy, greasy, or resinous luster of other stones.

The basic chemical formula of corundum is AL2O3 (aluminum oxide). It is the presence of trace elements like chromium, iron, vanadium and titanium which are responsible for the wide range of colors in which the mineral occurs. The red color in Burma Ruby is primarily a result of the presence of chromium. 

Burma ruby's passionate color is just one reason for this gemstone's popularity. As with all corundum, it's also extremely durable, having a hardness of 9 on the Mohs scale. Burmese ruby has a specific gravity of 4.00, a refractive index of 1.76 - 1.78, and birefringence of 0.008.  The refractive index (RI), measured using a refractometer, is an indication of the amount light rays are bent by a mineral. Birefringence is the difference between the minimum and maximum RI. When birefringence is high, light rays reflect off different parts of the back of a stone causing an apparent doubling of the back facets when viewed through the front facet.

Gem quality Burmese rubies are rare and  clean stones over 1 carat are extremely rare and garner the highest prices in the gemstone world.

Color    

Color is the single most important factor in determining the value of a Burma ruby.  Indeed, the color of a ruby is more important than its clarity. Burmese rubies are rarely clean and even very expensive stones can be slightly included. But subtle differences in color can make correspond to significant differences in value. Highly saturated medium or medium dark red tones are best, rubies which are too dark or too light are worth considerably less.

Although Burmese, African, Thai and Cambodian rubies have the same chemical and physical properties, they differ noticeably in color and hue, with Burma ruby being the top of the line gemstones…  Burma ruby displays a true red to pinkish red color in most kinds of light. Thai and Cambodian rubies are usually darker and browner in color, similar to garnet. Recently some fine African ruby has come on the market, from Tanzania and Mozambique. Though selling at high prices, they rarely exhibit the same fluorescent quality as the best Burmese rubies.

Cut

Ovals, rounds, cushions and emerald cuts are the most common cuts for Burmese ruby, due to the typical shape of corundum rough. Other popular shapes include pears, briolettes, hearts and  marquises.  Star rubies are cut into the cabochon shape in order to develop and properly display the star effect.  Inclusions of fine rutile within a star ruby reflect the light which causes a star to appear within the stone. A six-ray star ruby has three sets of parallel fibers. Skilled cutters can sometimes create a 12-ray star ruby but they are rare.

Source: https://www.ajsgem.com/gemstone-information/burma-ruby-32.html

https://thenaturalrubycompany.com/education/mining-locations-rubies/myanmar-ruby-mines/