Lavastorm Mountains. most critters give out stones when you kill them. This
is also a very good place to hunt in general from level 10 ( but not solo )
to level 16+.
the lava crawlers carry the best stones but they are level 15-16 and require
magic to hit. Lavastorm countains also 3 high level dungeons: najena, and
...cant remember the name of the others ( something like Nafulben and maybe
Solusek Ro ), but you dont want to go there anyway.
Make sure you have illusion Dark elf before you go there, because you will
have to cross Nektulos forest to reach lavastorm.
Skara