PROPERTIES – Aluminum oxide. It has a hardness of 9 which is highest after Diamond. The density is approx 4.0g/om3. It is available in all colors, i.e. Red, Yellow, Blue, Purple, Pink, Gray, Black and even colorless. It belongs to the mineral Corundum and is one of the most valuable varieties. The name comes from a Latin word “Rubrum” ie is red. In Hindi it is called Manikya or Lal. In Urdu i.e. Arabic, it is called Yakut. The most desirable color is “Pigeon Blood” i.e. pure red with a hint of blue. The distribution of color is often uneven in stripes or spots. The color varies from fiery vermilion to violet red. The brightest red and thus the most valuable rubies often have areas full f inclusions (Liquid or gas bubbles, healing cracks and foreign crystals) in the form of minute retile needles or straws, which interfere with the light, producing a distinctive silky sheen known in fact as silk. When the silk is not heavy, the stones are clearer, more attractive and even more valuable.
CUT – as a rough stone, Ruby appears dulland greasy but when after cut, the lustre can approach that of a Diamond. Rubies are generally given a mixed cut, which is mostly oval, but can be round or more rarely other shapes. In the past they were given a Cabochon cut, like all stones outstanding for teir colour. Today this cut is reserved for less transparent stones with numerous inclusions.
Distinctive features :- rubies can be distinguished by their immediately visible characteristics :- (1) a fairly obvious pleochroism. (2) a distinct brightening of color in bright and strong light (3) the silk effect(where present) (4) a considerable luster. While spinal (its resembling stone) can be a similar color and has a similar luster, it is not plecchroic, turns much less bright in strong light and never displays the silk effect.
Occurrence – the rubies with the finest color come from the Mogok region of Burma. Beside Burma, Thailand, Srilanka and Tanzania are having the important deposits.
Value – the highest quality, but colored and most transparent stones can be valuable than Diamonds. It is the most expensive gem.
The largest rough Ruby weighted 400ct, was found in Burma and divided into three parts. Famous stones of exceptional beauty are the “Edward Ruby” (167 ct) in the British museum; Reeves star Ruby (138 ct) in the Smithsonian institute, Washington and the Long Star (100 ct) in the American Museum New York.
These may be worn by under the Zodiac sign – Leo.