quarry methods

Quoted text begins.But I have run
across some pieces that were good for carving but did not ring well,at all.
End of quote.

Apologies for over simplification. Yes, some don't ring well but are
still usable and with practice and innumerable taps you can tell
somewhat where there is a solid piece under the crumble and its
approximate shape so while it isn't fool proof and can be somewhat of an
art in itself, tapping works and it is possible to get a silk purse out
of a sow's ear.