18k gold
75% pure gold, alloyed for strength and colour. Yellow and rose gold are solid colour; white gold is rhodium plated and benefits from re-plating every year or two.
Platinum 950
95% pure, naturally white, denser and hypoallergenic. It develops a soft patina rather than wearing away.
Hallmarking
Gold jewellery sold in India carries a BIS hallmark with a unique HUID number.
