How to value rubies

The appearance of a gem is the most important factor in determining its value. The three factors of color, clarity and cut determine the appearance of a gemstone and a guide to evaluate its quality.

As a matter of fact, color is the most difficult to convey even though the human eye can distinguish several million colors of varying hue, saturation and tone. Some thousands have been given names but having had words to describe them and to distinguish one color from another has been difficult. The basic color vocabulary of the richest languages has been pitifully a dozen words.

Color is a spontaneous experience combined directly or indirectly on the emotions, and sometimes it is difficult to understand. In the gemstone industry beauty is in the eye of the beholder, and there are choice preferences for different gemstone species. The ones who have been in the business have known from experience that there are selective color preferences when it comes to specific gemstones due to their geological, gemological and cultural significance. The objective of a color name is to convey the appearance of a given color. It should have a signature trait that others easily understand it.

One way is to look at our environment and find objects of typical color shades and names, which can be used to convey a characteristic appearance. This has been the case with colored stones, especially rubies and sapphires. Early gem dealers designated strength with depth of color. Deep saturated rubies with dark tones from Burma and Thailand were classified as masculine. While rubies from Sri Lanka with light tones were classified as feminine. In ruby producing countries many descriptive terms have become popular among the gem traders. In Thailand, Tabtim is a generic term for ruby but can be used interchangeably with Ploi-daeng, which literally means red stone. Daeng-chompoo: pinkish read, usually light in tone. Daeng-som: red with orange tones. Daeng-dum: dark, blackish red, with weak fluorescence resembling red garnet. Lai-thai(Thai motif or pattern): ruby with lots of wispy-like inclusions, which resemble the patterns on Thai textiles. In Burma, Padamya is the generic term for ruby. Ko-twe(pigeon’s blood): the top color of Burmese ruby resembling the color of the first few drops of blood from a freshly killed pigeon. Yeong-twe(rabbit’s blood): the second-best color of Burmese ruby, slightly darker and more bluish red than Ko-twe. In Sri Lanka, Rutheka is the Sinhalese term for ruby. Padmaraga(or padmarage or pathmarage): pinkish ruby(pink sapphire). Nilakantia: ruby with a blue tinge. Many colloquial names have also arisen for the different colors of sapphires.

In Thailand, Pailin is a generic term for blue sapphire. Bhusarakham (luang chantaburi): both these terms are for yellow sapphire. Bhus-namtaeng (namtaeng=yellow green Thai fruit): yellow tinted with green. Khiew-song (shining green): green sapphire. In Sri Lanka, Nila is the general term for blue sapphire. Indra-nila: best quality of blue sapphire, which is blue with tinge of violet, sometimes compared to the color of the tip of a peacock’s feather. Rabuka: a medium but intense blue sapphire. Pusparaga (literally flower king): yellow sapphire, from the Sinhalese word for pollen. Ratna-pusparaga: gold, yellow or orange sapphire. Padparadscha: orange pink sapphire, from the Sihalese word for lotus flower. Ottu (Tamil-to risk): sapphire crystal where the blue color is confined to a layer beneath the surface. Geuda: cloudy corundum (highly valued due to heat treatment).