Is There Really Such A Thing As A 100% Gold Coin, Item Or Whatever?

1) How much do you want to bet that 90% silver or gold coins aren't exactly .90000 (90.000%)?

2) At $1,228.11 per troy ounce, difference in gold value:
a) "pure" and .999 = $1.23
b) "pure" and .9999 = $0.13
c) .999 and .9999 = $1.10

3) At $17.91 per troy ounce, difference in silver value:
a) "pure" and .999 = 2¢
b) "pure" and .9999 = 2/10 of a cent
c) .999 and .9999 = 1.8¢

The "five nines" bullion coins are little more than a gimmick; a show of engineering might just as much as the 1,000kg gold maple leaf, or whatever country issued a micro-engraved coin with the entire Sistine Chapel.

Are you willing to pay more for a coin/bullion with an extra 9 (i.e., .9999 vs .999)?

Since it is so expensive to refine gold to the higher percentage, then the refiner either has to charge more for their bullion, which in turn results in higher costs for "raw" bullion, thus higher prices for minted gold coins and bullion.

I don't follow this close enough - are there separate market quotes for .999 vs .9999 vs .99999 coins/bullion?

If customers migrate away from .999 towards .9999, will this result in the long range contribute to a rise in gold prices?