What is the correct amount for the zakatable threshold (nisab) of 21-carat gold: is it 97.14 grams, or 97.2 grams, or 97 grams?

The nisab (minimum threshold) for gold is 85 grams of pure gold (24-carat). To calculate the pure gold content from 21-carat gold or other karats, multiply the number of grams by the carat and then divide by 24. If the result reaches 85 grams or more, zakat becomes obligatory on it, and one-quarter of one-tenth (2.5%) of it must be given.