or make the build harder then that imo...since they have a chance to dorp nothing or burned out lightstones how about something like this
9 Burned out lightstones + 1 light source(of any kind) = half light stone *rinse and repeat*
10 half light stones = 1 light stone
10 light stones = 1 minor lightstone
10 minor lightstones = 1 lesser lightstone
10 lesser light stones = 1 greater lightstone
that wahy its not an easy way out and takes alot ot get a greater so people will not be farming them out the wild...maybe make the light source 50k or something... I've noticed that timesink quests are good here so this is just another way to do that