pure gold is 24 carats.

Generally, this term refers to gold which can pass through a 40-mesh screen. It includes fine gold and dust, which, in your pan, will appear as colour so small that it can only be collected by amalgamation.

Fineness is the proportion of pure gold or silver in jewellery or bullion expressed in parts per thousand. Thus, 925 fine gold indicates 925 parts out of 1,000, or 92.5% is pure gold.