Last updateTue, 22 May 2018 10pm

The Story Behind the Stone: Ruby Talk


Rubies have been, throughout the centuries, one of the most coveted colored gemstones. Their rich eye-catching hues are the stuff that makes royal accessories look regal. They are more rare than diamonds, and their recovery from remote deposits is often more treacherous than the harvest of other precious gemstones.

Carmen Lucia ruby ring from the Smithsonian Museum of Natural History.
So dealers have done whatever it takes to make their ruby supply salable throughout the years. Treatments for ruby include heating to force a red color from a deep almost blackish dark tone. In fact, 13th century Egyptian gem trader Teifachi wrote quite a bit on the subject of beautifying ruby to make it sell.

“In Sarandib [Sri Lanka] and its environs, ruby is treated by fire. People take pebbles from the earth and crush and compress them into a mass with the aid of water. [This mixture] is daubed completely around a dry stone. Then, the whole thing is placed on a rock with other rocks set down around it. Dry firewood is thrown on top, lit and blown upon [with bellows]. The blowing is applied, along with more wood, till any black overtones on the ruby have disappeared.”

Rural gemstone traders still rely on this centuries old technique. They vary the amount of fire and wood depending on the extent of the blackness in their ruby rough. The stones get heat-treated for about an hour or up to a maximum of nearly three weeks. Then, they carefully extract the ruby to witness a red replacement for the blackish color. The process is never done more than once, since repeat heating will not further improve the color.

Fast forward to the 21st century and observe how modern merchants attempt to market their ruby. Whole new subsets of descriptions for the various processes imposed on rosy corundum are required. And retailers need to understand what they mean.

Here goes:

Lead-glass treated or fracture filled means that very low grade ruby, with no durability due to its abundant naturally occurring fractures, gets an infusion with lead glass, sometimes red colored. This binds the stone, and eradicates the appearance of fractures. Disclosure is critical since these stones should be sold cheaply. And they are not impervious to crumbling on occasion under the jeweler’s torch. They should be more descriptively identified as composite ruby. Some laboratories are calling this hybrid ruby.

Winza Ruby crystal in matrix.
In a free market, entrepreneurs should be allowed to sell what they want and let the consumer decide if it’s worth buying, and at what price. But the consumer must be apprised of what they are buying so their decision is an informed one.

Total disclosure on ruby treatment notwithstanding, this perplexing situation should give rise to another more profitable direction for retailers. Jittery customers may be appreciative of you offering other red gemstones to which no treatment has been applied. Ah, the allure of garnet, spinel and tourmaline; all known for their intense scarlet hues, and for being untreated to boot. Still, if nothing but ruby will satisfy, let the customer decide what verified natural ruby is worth to them. Sources for this abound in Madagascar, Sri Lanka, and Winza deposits in Africa.

Award winning trade journalist and gemologist Diana Jarrett is also a Registered Master Valuer Appraiser and a member of the National Association of Jewelry Appraisers (NAJA). She’s a popular speaker at conferences and trade shows. Jarrett writes for trade and consumer publications, various online outlets, and for sightholders and other industry leaders.. Contact her at This email address is being protected from spambots. You need JavaScript enabled to view it., visit her website, www.dianajarrett.com, and/or follow her on FaceBook and Twitter (Loupey).