I have been wanting one of these for a long time and decided to splurge. I first tried it on a piece of metamorphosed granite and it took too long to split it so i will stick to normal crystallized granite cobbles. The intent is to use them on stone walls. The other use I envision for it is to break up huge pieces of lapidary rough .If the rough has an incipient crack it works extremely well.It is a 4 lb hammer with a very sharp carbide edge and is designed to be used by striking the rock or as I prefer, placing the hammer where you envision a split and striking it with a 4 lb hammer. I am back on crutches and can carry very little weight so I need to be able to break rough in the field and break the huge pieces of rough in my yard.The hammer works very well for that leaving a very clean break so I can finally use some of the rough i have been staring at for a few decades.Nice tool.