The latest thread on this coin got me thinking about slabbed vs. OGP examples, and I suddenly wondered: How is pink gold likely to TONE? With more copper and some zinc in the alloy, I'd expect it to be somewhat more reactive than standard coin gold. And it's starting from pink, not gold. I wonder...
Look for toned specimens of Kugerrands or Israel coins both South Africa and Isreal have been minting using rose gold for years.
It depends on whether they get a good homogenous alloy, which they should because it will be made by an outside source like everything else. Good mix in gold will prevent oxidation. Have you seen any of the 14kt gold Canadian $100 pieces tone?
The mint says 85% gold, 14.8% copper, and remainder zinc ( .2%). https://catalog.usmint.gov/breast-cancer-awareness-2018-proof-5-gold-coin-18CE.html This compares with jewelry pink gold = 75% gold, 20% copper. 5% silver Rose gold = 75% gold, 22.5 % copper, and 2.5 silver, and red gold 75% gold and 25% copper. So I would expect stability and maybe slight changes towards the "pink shade of jewelers gold.
