Trade
Selling to Aislings
So, in the gem business, trade is always booming. A rogue will never fail to make themselves a good amount of coin through the gem trade. Many Aislings will pay upwards of 500,000 coins for a single uncut gem. They are the easiest to make as well.
This is due to the fact that many priests throughout Temuair will require many uncut gems. In exchange for knowledge, Narve the fae of Piet village asks for dozens of uncut gems to teach them how to cast strong white magic spells.
Wizards and some monks require finished gems to trade with various other mundanes in exchange for knowledge as well. Such as the kobold of Astrid asks for finished rubies, corals and talos so that a wizard can learn how to enact the ancient ritual to cast the spell of mor strioch pian gar upon their enemies.
Selling to Mundanes
Now, there are also mundanes who like to purchase gemstones from Aislings.
For example, in Mileth alone Cian the alchemist always purchases any type of coral fragments which he enchants into those coral earrings he also sells.
Torrance in the armoury will take any type of beryl, ruby and coral fragments. He crafts beryl and coral earrings as well as ruby rings to make his living.
Cassidy the Mileth banker also purchases those same three gems, which I would presume he sells or trades to the tradesmen of Mileth.
Abel banker Lamont purchases, finished beryls corals and rubies The armourer will also buy corals. To note here as well, the mundane of the storage shop will take talgonite and give you a fair price for it.
Having checked through the towns, it is a good bet that any armourer will buy your normal gem stones of most states and give you some coin for them. If you are a young Aisling and struggling for gold, it could be worth grabbing all the fragments you see whilst adventuring and taking them to town to sell them.
Abel and Piet are the only town that will buy any talgonite fragments that you may find wandering through Temuair. If you need to sell these it is best to head to either of these two towns.
If you are lucky enough to find fragments of hybrasyl then Oren bank is the only place you would be able to sell those. Balsamo is likely to buy those to sell the Jeweller there.