What is the average number of carats in an opal?

The average number of carats in an opal can vary significantly based on the type and quality of the stone. However, most opals sold in the market typically range from 1 to 10 carats. Larger opals, over 20 carats, are less common and can be quite valuable. The size and carat weight can greatly influence an opal's price and desirability.