Ruby & Star Ruby
a) Ruby - A Ruby is a pink to blood-red coloured precious gemstone, and a variety of the mineral corundum (aluminium oxide with chromium).
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The quality of ruby is determined by its colour, cut and clarity. The most valuable shade of red called ‘blood – red’, which commands a large premium.
All the natural rubies have imperfections in them which include colour impurities and inclusions of rutile needles known as ‘silk’. Rubies without any needle-like rutile inclusions indicate that the stones may have been treated. 95% of the world’s rubies are treated in some form, with heat–treatment being the most common at temperatures of around 1,800°C, to improve the colour, move purple tings, blue patches and silk. Such rubies are called heat-treated or naturally colour-enhanced rubies.
Another treatment is lead-glass filling of fractures, which is unethical and a deceptive practice. (Glass-filled rubies fill up the internal cracks, make the surface glossy and alter the mineral composition of original gems. This treatment will reverse and the gemstone becomes dull over a period of time).
Rubies have a hardness of 9 on the Moh’s scale of mineral hardness, as against 10 for diamonds.
LifeGem Diamonds Limited offer rubies as cabochons and faceted gems which are natural, un-heated and un-treated.
All our rubies come with a certificate from an external laboratory (for example, IGI), to confirm that they are un-heated and un-treated natural Rubies.
b) Star Ruby - Star ruby is a variety of ruby that exhibits asterism; a 6-rayed star that shimmers over its surface. The star is best visible when seen in a single light source.
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LifeGem Diamonds Limited offers star rubies in dark purplish-red colours. The shapes are round & oval, and the cut is cabochon. These are natural, un-heated and un-treated, with a moh’s hardness of 9. We supply them in 5 mm to 15 mm sizes.