When I was an active coin collector many years ago, I occasionally bought gold coins for their bullion value, so I had to know what I was getting. More recently, my wife sold some of her gold jewelry and I had to calculate the gold value based on the weight (in troy ounces) and the gold
fineness (karat value, as in 14K gold = 14/24 pure).
But this is fun.

When I was a kid the question was, "which weighs more, an ounce of cotton or an ounce of lead?" And the answer was they both weigh the same. The rules change when you substitute gold for the lead because gold (or silver or platinum) is measured in troy ounces.