Probably not much at all, gold leaf is flattened to 1/300th of an inch. So although they look nice, it's a very very small amount of gold by weight.
~~Do you have pictures? They sound pretty cool.~~
They're usually actually not worth their weight in gold. Gold foil decks typically go for under $10. Foil is a thin layer people use for a top coating, its not the whole card
Heres a set that doesn't look as nice but with the same certificate for like $7.https://www.amazon.com/Trademark-Poker-GLDCARD-Playing-Cards/dp/B00ARBZJCQ
Obviously OP's is a bit nicer than that and would go for a bit more, but its not like hundreds of dollars Heres a more similar set for $21, well less then the price of a brick of gold the size of a deck of cards: https://www.amazon.com/Idea-International-Gold-Deck-Cards/dp/B004CR5YI0?ref_=fsclp_pl_dp_9
I knew this was wrong before I found the proof.
I know Canada coins and bullion have one of, if not the purest mass produced stuff out there, and they're mostly onlt 99.999% pure.
Some select special issue is 99.999%. It's gonna be pricey. For cheap thin stuff like this, I figured it wasn't gonna happen.
Seems like you made the mistake of only noticing the 99.9% and adding an extra 99 on top.
Nice Kershaw and pic though. I just like accurate information and representation of things.