24K vs 22K vs 18K: gold purity, explained

Karat measures purity out of 24 parts. Here's what that means when you buy.

• 24K (999) — 99.9% pure. Too soft for jewellery; ideal for coins, bars and digital gold.
• 22K (916) — 91.6% pure. The Indian jewellery standard: rich colour with enough strength for daily wear.
• 18K (750) — 75% pure. Harder alloy that holds diamonds securely; slightly paler, noticeably lighter on the wallet.

Reading the hallmark

Every Aurora piece carries the BIS triangle, the fineness number (916/750), and a HUID — a unique alphanumeric ID you can verify in the BIS Care app. Your invoice lists the same HUID.

Which should you buy?

Traditional and bridal pieces: 22K. Diamond and everyday minimal jewellery: 18K. Investment: 24K coins or digital gold, which we buy back at the live rate.