Currency

the Old Lore mandates stuff like glass rings containing valuable sand. I think I could expand this to other rings also, and the occasional glass ampoule for sand, but I like it. what funky things will I do with the valuable sand, and how will they prevent people putting food dye in boring sand as fraud? leaded sand which has distinct weight/volume relation? manmade sand with distinct crystalline structure?

I think I'll simply do what I always do and regional-variation the currency.

• sands hold value further from the desert & crystal fields, metal rings appreciate further from the mines, the occasional village refuses to trade in anything but bones, and lots of places you can trade your reasonably standardized gems. especially gems you'll probably need to exchange for locally relevant currency to buy stuff most places, since the average food hut doesn't do spectrum stuff and microscopy.
  • sand verification requires taking it out of the ampoule/ring, carefully so as not to spill any. this takes time and trust, and may not be bothered with if you're just running by somewhere for a fried snake. this can be an assurance against fraud.
  • sands make a more portion-able format of gems, but in return ofc one that's easier to fake. dyed spinel grains instead of ... idk taaffeite. but then it's difficult to try buy groceries with a formidable glob of olivine without overpaying something fierce, so subdivision is convenient and necessary too.
• rings seem the most convenient, but they make it very apparent to those around you how many mugs of sap you can afford tonight. less trusting communities might not favour this.
• centralized vs localized currencies give +1 duty to the postal service, namely verifying exchanges for those not in the local know, slightly more reliably than random merchants depending on the bribe.

story: a presmly quite coastal locality that traded with the outside world Once through then-cheap whale bones, took a 200 year break from the world, and now refuses to trade in anything but a very expensive commodity thereby inadvertently becoming a small financial powerhouse.