Just exactly how rare is an unheated ruby? Regardless of its origin?
Much has been said and written about the differences in value between an unheated and heated ruby. In addition, there is also a category reserved for “glass-filled” or “lead-filled” or “lead glass-filled” rubies. These 3 terms pretty much mean the same thing, which essentially means, rubies that have been filled with high-lead-content glass, which made the rubies appear more transparent after the treatment process. Filling ruby material with lead glass enabled what would have been nothing more than material specimen mainly used for gemological studies; definitely nothing of decent commercial value. In addition, filling gemstones with lead glass actually adds carat weight to the material. What does this mean for end consumers? Essentially, consumers will pay more for glass instead of gemstones. More can be read about lead-filled rubies here: https://www.gia.edu/doc/SP06A2.pdf
Heated rubies in our present, modern-day gemstone and jewellery market have become more commonplace because it remains a fact that unheated, 100% natural rubies oftentimes, have a lacklustre and dull appearance. Ruby material is heated to improve the colour and clarity of the rough and ultimately, the polished gemstone. It is important to recognise this because it impacts the price differences between heated and unheated rubies and the market premium accorded to unheated rubies. Without the heating process, commercial quality rubies would have a lot more eye-visible inclusions, opacity and dullness, which would result in these rubies being unable to be sold at fair prices or worse, not sold at all.
Unheated rubies as mentioned above, are typically heavily included with a dull appearance. To understand it in a nutshell, as this article aptly describes: “Very few of the recovered rubies are of high enough quality to be sold on the market. In fact, only about 1% of all corundum found is gem quality. Of those rubies, only a fraction remains untreated.” https://thenaturalrubycompany.com/education/ruby-characteristics/ruby-rarity-value/
Let’s all take a moment to consider this statement: of the 1% of all corundum mined from earth being gem quality, only a fraction of this 1% remains untreated and unheated.
“Gem quality” usually means a gem has the aesthetic appeal to the human eye. Eye-clean, with even colour tones throughout the gemstone, with good brilliance and lustre.
Seen below is a rare unheated 1+ ct ruby, set in diamond halo with 18K Natural Gold. It is becoming increasingly difficult to source for eye-clean unheated rubies that are facetted and polished with a nice finish and cutting symmetry. In addition, unheated rubies are almost always presenting themselves in a somewhat dull and lacklustre appearance, oftentimes looking somewhat cloudy.
To find a ruby that checks the following will involve more than just luck:
3. Lively appearance with fair – good brilliance. Not dull and not cloudy looking
4. In a properly facetted, well-proportioned symmetry