Trading in shards with currency exchange

I am very happy with how the in-game currency exchange works, except for when I am trying to sell something like harbinger orbs. This is currently around 5.8div each, which is a very fair price in itself, but unless I have 5 orbs to sell, I could only list it at 6d each which will basically never sell.

I am proposing the following changes:

(1) Add divine shards to the game with stack size of 20
(2) In exchange, allow input of fractional values (up to multiples of 0.05) if that side is a currency with shards, and match orders with shards. Accordingly, shards themselves no longer appear as valid option in exchange.
(3) Add some way to break a currency down to 20 shards outside exchange. I'm not sure what's the best approach for this part, however.

Happy to hear alternative proposals and critiques of this plan.