Gem Merchant Hou collects the stones of Human, Heaven, and Earth given out as quest rewards and combines them into Celestones. This, roughly speaking, sets the price of Celestones in the Perfect World economy. Since anyone can combine 9 stones that sell for 1,000 apiece into a Celestone, the price of Celestones is loosely tied to 9,000. Obviously the disadvantages of having to collect three of each (inventory space, getting even amounts of each, and sheer time consumption) prevent the service of Celestone sales from dropping very near 9,000, but it cannot rise much above 15,000 before another factor, the competition from other merchants, combines with the stones' base price to drop the price again.