Coins

[Juggernaut1981]

The immediate problem is that you'd be forcing yourself to hand out to commoners items of magical powers. I don't know if you want that to be the case, but as Lord Such-and-Such I don't think I'd like to be handing out rare magical gemstones to Jimbo the Fishmonger.
It might be easier to create a two-tier currency, where these magical coins are used for the top-level transactions.
Also realise that you're now potentially setting up a world-level economy, which we don't even have now in the modern age(we just have a "we'll accept it everywhere" currency of USD, but how long that may last is debatable).

[290blue]

I like these a lot in concept, and the designs are very nice. I'd be okay with the "magical items in commoners' hands" thing, depending on the magical level of the world. I don't think they even need to be a global currency, just the coins issued by The Magical Nation of Whoever (which might end up being more widely accepted by merchants from other nations).

However, I have a different problem, and that's that these don't seem practical for every day use. The gem in the middle makes them completely non-stackable. A pocket full of these would be awkward. Anyone trying to count them (bankers, gamblers, dragons, etc) is going to have a hard time.

I think they'd work well as an "upper tier" of currency, as Juggernaut suggests; something like platinum pieces or astral diamonds that would be rarely used in every day transactions.

I'm interested in what you had in mind for the infusions, though. Can these infusions be released, like a potion or scroll? Or were they just meant to indicate a different denomination of the same base coin?