How the gram price is derived
Although South African shops quote per gram, the global market quotes gold in US dollars per troy ounce. One troy ounce equals exactly 31.1034768 grams, so the pure gold (24K) gram price is the ounce price divided by 31.1034768, converted to ZAR at the live exchange rate. Lower purities are then a simple multiplication: 22K/916 is the 24K gram price × 0.9167, and 18K is × 0.75.
South Africa was for decades the world's largest gold producer, and the rand gold price remains a key industry metric — mines earn in rand while gold is priced in dollars, so the USD/ZAR rate strongly affects local prices and mining profitability.