Purity of Gold
       Purity of Gold is known in 'carat'. Gold in its pure form is 24 carat (99.99%). Copper is added to improve its color tone to slightly reddish. Adding of copper gives more mechanical strength and reduces its wearing defect to gold ornaments. Normally 22 carat gold is widely accepted for Ornaments.
What is 22 carat (22 ct.)
   As mentioned above copper is added to gold for ornament making. Two parts of copper is mixed with 22 parts of pure gold. Thus the purity of 22 ct. gold is 22/24 * 100 = 91.67%, commercially known as 91.6% purity.