I've always loved the way copper patinas over time!
Yeah, those
BTC pennies look even better once they've toned.
Do you know the exact composition of these coins? The OP says this:
Our coins are minted in the USA out of high grade copper for a quality coin that gives a nice R-I-I-I-I-I-I-I-N-G when you flip it!
....but it isn't clear what the metal composition is of the coins. Are they the standard zinc/copper formula that the US mint uses, for example, or something else? I'm just curious to know. Either way they do seem to age well based on the pics shown here.
Edit:
Bitcoin Penny™ Commemorative Coins are ninety-seven percent (97%) copper. The other 3% is a special proprietary formula belonging to the mint.
Thanks for the answer--I wasn't sure if it was a secret or if you'd mentioned the composition elsewhere. And yeah, at 97% Cu, that's even higher than the pre-1982 US pennies that I've been hoarding for a while now (I know some of the '82s are 95%, but I don't have the patience or a scale to separate them). The new, mostly-zinc pennies look nice and shiny when they're just released, but they definitely don't age half as nicely as yours do. Props on a nice-looking collectible!