Venore, 1 floor up. The white circle is where he stands.

Start with hi. Then:

100 gold = 1 platinum · 100 platinum = 1 crystal. One crystal coin is 10,000 gold and weighs the same as one gold coin, which is the whole point.

Say change gold, change platinum or change crystal, then how many you want, then yes.

Going the other way, change platinum asks first whether you want gold or crystal. There is no bank account in this version: nothing is deposited and nothing is kept for you.