List one stack of 10 ingots at 5000g (500g each) and see if it sells ... doesn't sell in a few days, cancel the listing and relist lower.
If your Guild store already has some listed, slightly undercut that listing as a starting point and see what happens.
Once there are many V9+ players you will find end game materials actually selling for less than some of the earlier zone materials .. it depends on how long someone is in a particular zone leveling that determines the amount of product on the market. You are in end game zones for much longer and will have ready access to materials for end game crafting.
less product, good demand = higher prices