The tiny numbers engraved on gold indicate its purity level. The number 916 is the most common stamp found on gold jewellery in India, and it means the piece contains 91.6% pure gold, equivalent to 22 karats. A 750 stamp means 75% pure, 18-karat gold, while 585 indicates 58.5% pure, 14-karat gold. The number 999 represents 99.9% pure, 24-karat gold.