Hi all I am opening my collection to platinum coins for the first time. I bought a Australian Platinum Koala 1/10 oz, year is 1990. I checked its measures to evaluate the content. It turns out to be 3.16 grams, diameter 16.04 mm, thickness 1.11 mm. The last parameter puts me a little off. According to specs, the coin should have a thickness of 1.40 mm. I never had a coin so off in thickness, although technically the density is higher, and platinum has the highest density among normal metals, so I can't see how it can be counterfeited. Can anyone with the same coin confirm the measures of thickness, or eventually explain where the problem is ? Will I have problems reselling it with such difference ? Thanks
thickness is the hardest dimension to measure. I believe that technically, you're supposed to be measuring the rim. If the edge of your calipers are inside the rim, you'll get a different reading. Also, there tends to be variance in rim thickness from the minting process. Also, you're not supposed to squeeze the coin in the calipers or you'll get a different reading. I wouldn't worry unless one of the parameters is grossly off. Also for gold and platinum, usually the only time you need to be concerned is if the coin is bigger, not smaller. Say you measured the thickness, and it was 3 mm instead of 1.4mm. There aren't many metals that can be used to fake gold and platinum that are denser. Commonly used metals such as copper, nickel, iron are all less dense, and one of the attributes (weight, diameter, thickness) would be way off.
