The number 916 on gold jewelry indicates the purity of the gold in parts per thousand. Specifically, 916 refers to 22-karat gold, which comprises 91.6% pure gold and 8.4% other metals such as silver and copper.

Gold jewelry is often alloyed with other metals to increase its strength and durability, as pure gold is soft and malleable. The karat system measures the purity of gold, with 24-karat gold being 100% pure gold. Therefore, 22-karat gold is a high-purity gold alloy used worldwide to make jewelry, coins, and other decorative objects.

The marking of gold jewelry with its purity in karats is often required by law in many countries, as it provides consumers with information about the quality and value of the gold. When purchasing gold jewelry, you need to look for these markings to ensure you get what you are paying for.