Choosing the right hammerstones for you

 Choosing the wrong stone for the wrong task causes many people to give up on hammerstone percussion. Knowing what size to use is also an important factor. For spalling, you should use one made of basalt or metamorphosized quartz. For biface work, use quartz, basalt, granite, hard limestone, etc.  I also of heard that you should only expect to remove a flake half the weight of the hammerstone.