I live in an area with a crazy variety in geological formations. I have been trying all sorts of rocks on steel since I was a kid. I can't imagine the torture that some of my pocket knives have endured. It has been a long quest. At this point I don't have a clue as to how big the vein is other than it is about 18" wide at eye level and the bluff is about seven feet tall but no saying it goes all the way up. The sample from either side are not good. For lack of better words it is too loose on one side and the quartz crystal are really big on the other.