The imitation candy agate could be defined as a new type of epoxy-filled chalcedony which shows similar colored cores to natural candy agate. The most effective non-destructive methods for identifying this product are Raman spectroscopy and microscopic observation. If doubtful always consult a reputed gem testing laboratory like the GIA.
Spinel is rarely treated, but some heated spinels are available in the gem trade due to demand. This report by researchers at GIA is a must read for gemologists, gem treatment specialists, gem dealers, jewelers and consumers.
Fourier transform infrared (FTIR) spectroscopy is considered a useful tool in revealing heat treatment of corundum. The report by GIA researchers is a must read for gemologists, heat treatment specialists, gem dealers, and consumers.
Untreated colored stones are becoming very rare these days.
Consumers beware. If doubtful, always consult a reputed gem testing laboratory like the GIA.
The majority of fine-quality Shi Zi Hong agate, one of the most famous color varieties of Nanhong agate comes from Liangshan Yi Autonomous Prefecture in Sichuan Province, China. The price is higher for the highly saturated orange red color variety with a fine texture. Since it is a popular colored stone in China, consumers in the market looking for Shi Zi Hong agate must expect plenty of treated and imitations varieties.
It is unclear why anyone would go to the trouble to treat a synthetic ruby with lead-glass filling, consumers and gemologists should be aware that such material does exist in the gem market.
Fissure filling in emeralds can be detected with a variety of methods. Standard and analytical methods are used by practicing gemologists to observe and identify distinctive fillers. Take note.
Any gems with surface-reaching fissures can be oiled. The purpose is to improve clarity. Consumers and gem dealers beware.
Oiling can have a significant impact on the clarity of a gemstone. Having lived in Southeast Asia for over two decades, I have seen it all. It's an art. Buyer beware.
In Thailand, glass and dopping varnish is commonly used to treat black star sapphires for variety of reasons. Buyer beware. If in doubt, always consult a reputable gem testing laboratory.
