Piet Bank
Jilt the banker of Piet bank does not mind if a rogue would prefer to polish gems indoors rather than outside at the mercy of the weather. The perk of smithing gems at this bank is that a rogue can directly deposit the gems without the need to stop what they’re doing and make a bank run.
A small note to make here is that gems cost different amounts of gold to be banked in your storage deposit unit. So uncut gems cost a little less than a flawed or finished gem would cost.
This is because uncut gems can just be thrown into a box with the rest of the uncut gems you deposit.
A flawed gem can be thrown into the same box, but a small piece of cloth must be wrapped around the gem to stop it scratching other gems in the same box.
Finally, a finished gem costs the most and this is because they are to be stored in small boxes for each individual finished gem, wrapped in cloth to protect its' delicate surface.