Before buying gold, it is important to know several things, from purity and hallmarking to price and wastage. Here is something that you ought to know regarding the difference between KDM gold and hallmarked gold.
To understand KDM Gold, we will have to know the process of jewellery making. Gold in jewellery form is put in shape by soldering as gold in itself is very soft. Solder is an alloy of gold and some other metal and has a melting point lower than gold such that in the process only solder melts and joins gold pieces together without affecting gold.
For a comparably longer time solder of gold and copper in the ratio of 60% and 40% respectively was being used owing to its strength. However, as the purity of this solder is merely 60%, when the jewellery is melted the resultant purity level obtained is less. So a 22 carat jewel crafted using this technique upon melting in case of sale will have a purity level of say 20 carats.
To counter this copper was replaced with cadmium owing to its lower melting point and liquidity. And as gold and cadmium can be mixed in the ratio of 92% and 8% respectively, the resultant solder retains the purity level of 92%. This gold crafted using cadmium is known as KDM gold as cadmium is also known as Kadium at some places. Upon melting this gold, it shall have the same purity level.
Health hazards with KDM gold
However, the use of cadmium in jewellery making resulted in health problems to the artisans as well as its wearers, so the Bureau of Indian Standards or BIS banned it. And now solders of Zinc and other metals are being used. This has ensured that there are no health worries. There were also skin allergies that have now been eliminated due to the ban.
Hallmark on gold is nothing but the quality certification awarded by the Bureau of Indian Standards (BIS) to gold. The certification marks that gold is of the quality as claimed by the seller. BIS evaluates the quality of gold and checks whether it meets and conforms to the international as well as national purity and fineness standards. This evaluation is exercised in the assaying centres of BIS spread across the country. Clearly, the difference between KDM and hallmarked is the metal used for alloying and purity.
What to look for in hallmarked gold?
Further a hallmarked gold is engraved and features the following details including the BIS logo, logo of the retailer, logo of the assaying centre, purity level and year of certification. An hallmarked gold is available in purity of 23 carat, 22 carat, 21 carat and 18 carat. Purity of gold is nothing but the total percentage of gold in the metal. 24 carat gold is 100% pure. So, for buying best gold always go for a BIS certified hallmarked gold.