Press Room: 05 Jul 10
Anchorcert sees a flood of glass filled rubies
AnchorCert gemmologists have seen a large number of glass filled rubies in recent weeks, many of which have been bought in good faith as being natural and untreated.
Senior Gemmologist Anu Manchanda explains “This type of treatment has been around for a few years now, but we seem to have suddenly seen an unusually high number.”
In their natural form these stones are poor quality, dirty corundum. They are subjected to bleaching to remove dark patches of colour but this also affects their structure making them brittle and unstable. Molten coloured glass is then used to fill the cracks. The resulting rough gem can be cut and polished but will always have a characteristic lack of clarity – rather like a boiled sweet.
A trained jeweller can easily detect such treatment as 10 times magnification will reveal bubbles, blue flashes of light and evident fractures running up to the surface under reflected light.
In spite of this the practice continues with the glass content of some rubies being over 50%.
The benefit of the AnchorCert service - the only laboratory in the UK to receive accreditation to ISO 17025 from UKAS – can be measured not only in the confidence and reassurance it offers purchasers, but also in the financial benefits that sellers achieve when selling stones that carry an independent, recognised and accredited certificate or report.
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