Chienkun stones are mostly used to preserve refinement, socket amounts and gems.While they are rather expensive, people generally use them to transfer high refinements and high grade gems. Here is link with charts to help you find out how many stones are needed to transfer your gear's refinement, sockets or gems.
Boutique pricing
Regular - 9.00 Gold (10 Chienkun Stones) or 1 Gold (1 Chienkun Stone)
Sale - 4.50 Gold (10 Chienkun Stones) or 0.50 Gold (1 Chienkun Stone)