Hallmarked gold under BIS scanner

The Southern region of the Bureau of Indian Standards (BIS) has intensified its market surveillance of the hallmarked gold jewellery sold in the city towards ensuring consistency in the quality of such jewellery.

Of 20 samples taken from various showrooms since January, the BIS tests found that two of them did not conform to the hallmark standard. The samples were tested at the referral assaying laboratory in its premises in Taramani here, which is the first such facility of the BIS, according to officials.

The team of officials involved in the drive to collect market samples of ISI products also take samples of hallmarked ornaments every alternate month. Officials said a total of 81 jewellers in the city have obtained licence to use hallmark on their jewellery. Hallmarking is done at private laboratories approved by the BIS and the exercise is to counter-check adherence to quality standard.

The samples collected from the jewellery stores are checked in carat meter to ascertain whether it adheres to grade of purity. For instance, 22 carat gold, which is largely used in Chennai, has 916 parts per 1,000 as pure gold. The sample is then tested using fire assay method to determine the value of pure gold used to make the ornaments.

“About 250 mg of gold is required for the test. We take two or three grams of gold as sample to use it in case of repeated tests. The remaining gold would be returned to the jeweller,” a senior official said. The jewellers are informed about deviations in degree of purity and are asked to exercise caution and rectify them within few months as per IS 1417:1999. Such jewellery stores are closely monitored.

The lab of BIS has received a total of 114 samples from across the country, including Ahmedabad, Visakhapatnam and Bhubaneswar since January. The BIS hallmark consists of five components - symbol, fineness number, logo of the hallmarking centre, code letter representing year of marking and jeweller's identification mark. While some of them are punched, some of them are laser marked in the ornaments to avoid damage, the official said.

More such testing facilities of BIS would be established. On the KDM mark found on some jewellery, the official said, “it pertains to use of Cadmium in the jewellery. It is not a BIS standard and is a misnomer to consider it as hallmark. We do not permit Cadmium soldering in gold ornaments as it is carcinogenic. We have instead trained goldsmiths to use other soldering materials. Consumers must look for 916 fineness number and hallmark when they purchase 22-carat gold.”