Currency Talk

[Reece]

Personally, if I were a Secondary, I'd probably keep a few of each type of coin (or some other counterweight) on me to measure their weights. If a customer pays in OM of any sort, just apply the price to one side of a balance and have them equalize it on the other. Now, this was a common practice back when they they measured coin value by its weight or whatever. I've seen in movies, at least. It's also common to see merchants fudge the values of their counterweights before, but those are the more unscrupulous ones.

Yeah, not a bad idea... except for the fact that density =/= weight:

Also, let's remember the actual Rules post about Omnilium:

It has been theorised that omnilium represents value itself. It can take many forms. When held by a Prime, it absorbs into their being and becomes a kind of essence that cannot be given or stolen, only used. It can take many physical forms, but the default is a kind of malleable sphere that can be split or combined at will, instantly reconfiguring itself to the same shape, size and weight but changing in 'density' depending on how much actual omnilium the orb represents. While anyone can split and recombine omnilium, secondaries cannot hold it within themselves as Primes can.

The important part is bolded and underlined.

It's a fair bet that everything shrunk in the Omniverse also follows this rule (otherwise any human-sized characters would end up weighing WAY too much if they actually ever shrunk themselves down to, let's say, a couple inches tall, via the Shrink power), so simply weighing coins wouldn't actually tell you anything.