Trade one of these to a Voidwatch Officer for a free chance at obtaining any combination of ores/ingots/logs/gems worth up to but not exceeding a value of 6k.
*NOTICE* Even though Voidwatch has a stock option now, you cant trade more than 6 Voiddust to a Voidwatch Officer for Voidstones. Meaning you cant trade 100 Voiddust an instantly stock 100 Voidstones. You have to trade 6 Voiddust an get 6 Voidstones, Fight whatever VW NM x6 then have to go back an trade 6 more Voiddust.
On top of Conquest Points, these can be purchased with Imperial Standing Points and Allied Notes by speaking to a Voidwatch Purveyor in ToAU and WotG areas respectively.
I found going to the past participating in Campaign fights accumulated far more allied note far faster and it still only costs 2000 notes per dust so nice easy money maker + exp maker if your bored.