Someone recently asked me to cut a seal for them from a stone they had purchased in China—a cream colored stone with a few dark brown spots. When I tried to cut the seal I found that the darker material was much, much harder than the softer stone which surrounded it. So hard, in fact, that it could not be cut with my seal carving knife. When you go to a store that sells seal stones and you find a multi-color stone ask the shop owner for a seal carving knife and lightly scratch or poke the different colors (on the flat base only!) to check for harder and softer spots. A stone may be uniformly hard or soft but if it has both it will be almost impossible to cut well. Any legitimate stone seller will allow this (and should be used to the request)—unless they sell expensive stones more for the beauty of the material than for their use in seal carving. You might take it for granted that an expensive stone should be carvable but, as always, it’s buyer beware.
Hard, Soft, or Both?
Written by Lu