Purity of 24-karat gold: If you are buying gold coins, gold bars of 24-karat this Dhanteras and Diwali, it is important to understand the purity level of 24-karat gold. A buyer should check the purity level of 24-karat via this as well before buying. This will help you to know if the 24-karat gold you are buying is of the purest quality.