Today I came across some lead glass ruby rings being sold with very misleading information – or lack of it. As a gemologist it saddens me that customers are still not being fully informed. Rubies are classed as type 2 stones due to the visible amount of fractures and inclusions found within them, it adds to their character and beauty. Jewellery quality rubies over 1 carat without any eye visible inclusions can be found, but are much rarer and harder to obtain. Ruby & sapphire are routinely heated. In fact 97% are routinely heat treated to improve colour and clarity. Because of the natural fractures inside ruby it was discovered in the 1990’s that whilst routinely heat treating ruby, it was possible to add lead glass to fill the fractures. This then became the treatment of choice for worthless unsaleable rubies. Once the ruby has cooled the lead glass sets and fills the fractures and therefore raises the clarity and the overall look of the stone. You can buy lead glass filled rubies for a few dollars per carat as these are non-durable stones. It is not a permanent treatment and it is not an industry accepted treatment either.
Each gemstone has its own specific gravity index which is basically the density of the stone. This unique index is one of the gemological tests we...
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