The Gem and Jewelry Institute of Thailand (GIT) has issued a warning against so-called cloned gold, a widespread type of fake gold made of metals thickly coated with real gold to make it difficult to tell if it is real or counterfeit using basic gold testing techniques.
Duangkamol Jiambutr, director of the GIT, said the institute is getting an increasing number of requests to test the authenticity of gold items, including gold bars, many of which turn out to be cloned gold.
The basic testing techniques such as filing the surface of the gold or scanning it fail to peer deep enough to find the fake content inside.
Many fake gold items appear genuine as they have a thick layer of gold on top which prevents the metal inside from being exposed, she said.
"The fake gold is increasingly found among gold bars which were being traded in the market. Most of them contain a tungsten bar inside which is thickly coated with real gold," she said.
"They weigh exactly the same as a real gold bar."
In some cases, the fake gold bars were found to have either lead or brass inside them, she said.
Aside from gold bars, the GIT has been told some Buddha images purported to be made of pure gold are in fact hiding other metals inside them, she said.
Most of the fake gold items are sold over the internet at unusually cheap prices, she said.
"Using ultrasonic waves in a lab test on gold items suspected to be fake, the institute has made several discoveries of fabricated gold," Ms Duangkamol said.