A BIS HUID number check is an important step when buying gold jewellery in India. This guide explains what HUID means, how the 6-character code helps identify an individual hallmarked jewellery piece, and how buyers can verify it through the BIS Care app. Learn about the three key marks on hallmarked gold: the BIS logo, purity mark such as 22K916 or 18K750, and HUID. The guide also covers common buying mistakes, itemised billing, purity checks, making charges, and practical tips to verify jewellery before payment.