by Nasrina Parvin Khan
Star Ruby is a type of rubies, which shows the special optical phenomenon “asterism”. “Asterism” is a phenomenon by which a star shaped light effect has been shown across the surface of the gem through the reflection or transmission of light.
‘Red’ is the color of passion, love, brightness and power. Every women as well as men are fascinated with this color .If we get a gem with color ‘red’ it will be a pleasing experience for us. It will fulfill our desire to get a gemstone with red.
Is there any gemstone in ‘red’? Yes, it is “ruby”. Ruby is the most passionate as well as most precious gemstone in this Earth. The most important characteristic of this gem is its amazing color.
The name ruby was came from the Latin word ‘rubens’ which means red. This excellent colored gemstone is considered as the King of Gemstone.
India was considered as the classical country of rubies for a long time. In the Sanskrit (on of the classical languages of India) ruby is called ‘ratnaraj’ which translates as “King of the Gemstones”.
Other important characteristics of ruby are its excellent hardness and brightness. On the Moh’s scale this splendid stone shows a hardness of 9, just after the diamond, the gravity is also high of this gem. It is 3.97- 4.05.
Rarity is another important thing about ruby. Ruby is an extremely rare gemstone. Especially finer quality ruby is very rare.
Ruby is the red variety of the corundum mineral. Actually the pure corundum has no color. Inclusions of little bit of other elements like, chrome, iron, titanium or vanadium are responsible for creating the color ‘red’. The ingredients of ruby are Aluminium oxide (Al2O3) and chrome with smallest proportions of other trace elements. But all the things are depends on the respective occurrence. Actually chrome is the element, which awarding ruby it’s amazing color deep inside the core of Earth, since the creation of the gemstone.
Ruby occurs in metamorphic rocks, diplomatic marble and gneiss. Usually corundum mined from secondary alluvial deposits. Very rarely, it is mined from primary deposits.
There are various kinds of rubies. But the most rare, valuable and attractive form of rubies is Star Ruby.
WHAT IS STAR RUBY?
STAR ruby is a rare variety of rubies. Nearly 3 stars are discovered in every 100 faceted corundum mined. Fine stars are more rare.
Star Ruby is a type of rubies, which shows the special optical phenomenon “asterism“.
“Asterism” is a phenomenon by which a star shaped light effect has been shown across the surface of the gem through the reflection or transmission of light.
Star Ruby is one of the most popular star gems, which shows an illuminated, wavy star bellow the surface of the crystal.
Usually Star Ruby shows the six legged star effect. But it can shows four to twelve rays depending on the crystal system of the gems. Twelve rays star effect in ruby is very occasional.
WHAT CAUSES STAR EFFECT
Star effect or “asterism” is caused by the dense inclusions of tiny fibers of foreign particles in gems. Generally, these inclusions are the reason of the reflection of light and form a wavy star like formation, which moves around when the mineral is rotated. All the inclusions in the gem are form via exsolution.
Solid crystal inclusions found within the corundum ruby. Some rubies leave holes or empty areas in the host, which filled with liquid, gas or solid. Reflection creates from fibers or fibrous cavity in the crystal.
The inclusions must be long, very thin needle like which called as ‘rutile’. “Asterism” is produced when the light is concentrate into 3 rays that intersects at right angles to the direction of the needles. Thus we get a six-rayed star. Small needles of rutile sometimes called ‘silk’ are oriented inside the minerals in the direction of the crystal growth system. There is relationship between the gem’s growth and the number of rays produced by the reflected light.
The arrangements of needles in a hexagonal pattern produced six-rayed ‘asterism’.
Exsolved inclusions form a pattern in the host mineral to form a star. This pattern remains same in case of ruby. The rays of star should cross at the top of the ruby and must be distinct.
QUALITY OF A STAR
The sharpness and the size of the star in ruby depend on the quality and quantity of rutile needles. We get a better star in ruby when the rutile packed more densely. Longer needles also produce a better star than the tiny particles. When the quantities of needles are much more, ruby turned into a low translucent stone and lack ‘asterism’. It also harms the color of ruby.
CUTTING OF A STAR RUBY
Cutting is very important to exhibit the star effect in ruby. Proper cutting helps to extracts the beauty of the gem. To display the star effect in best way, a ruby must be cut as cabochon with the girdle, parallel to the needles. Medium to high cabochons need to be cut to get a perfect star in ruby. The domed must be round or oval shaped.
COLOR OF STAR RUBY
The color of ruby is red. But the Star Ruby usually is not red. The Star Ruby available in red/pink or pink/red. Star Ruby from Sri Lanka is purplish brown. Generally the pinks have the best stars. Star Ruby with color ‘red’ is very very rare and costly. Red ruby with a perfect star are quiet impossible to locate.
COST OF STAR RUBY
The cost of red Star Ruby can reach at $50,000 per carat. Generally, three-carat pinks Star ruby sell for about $2000+ per carat whereas reds begin at about $5000 per carat.
The value of a Star Ruby influenced by the intensity and attractiveness of the body colors as well as the strength and sharpness of the star. All six legs of the star should be straight and prominent.
OCCURRENCE OF STAR RUBY
Finer qualities Star Rubies mainly come from Mogok of Myanmar and Sri Lanka. Mogok material is the most fascinating. In the other hand African and Thai corundum do not produce stars due to the lack of rutile in the host material.
FAMOUS STAR RUBY
The most famous spectacular Star Ruby is over 138-carat Rosser Reeves Ruby, which can be seen at the Smithsonian. It was mined in Sri Lanka.
Ruby mineral specimens
Buy Star ruby at gemhut
Burma Star Ruby