This has been true throughout history. The portability and liquidity of gold coins continues to attract investors. Only if they appear to have been tampered with, do they require additional assaying cost when sold. Their value is based primarily on their gold content. The four most popular gold coins all contain exactly one Troy ounce of fine gold, although their total weight will vary based on gold fineness.
Fineness represents the purity of gold.
A 24 Karat coin is pure gold or .999 fine. Less pure gold is perfectly acceptable in gold coins as long as the total weight and fineness of the gold content is indicated. Of the four most popular coins the Maple Leaf is the only pure gold or .999 fine coin. However, all four contain exactly one Troy ounce of gold. The most popular coin is the American Gold Eagle.