Question: What is meant when a stone is said to have a bedding plane?
What does a sculptor need to know when working on a stone that has a bedding plane?

Answer: (In answering this question, NWSSA member Bill Laprade had this response):
Bedding planes are developed in sedimentary rocks.  They are the planes between individual layers.  The planes can be microscopic or thick and made of different material or different size particles than the dominant rock type.  Because the planes are commonly (although not always) weaker than the rest of the rock, the rock tends to split along the bedding plane.  A sculptor needs to check the stone strength parallel to the bedding.  When working such a stone, do not strike parallel to the bedding.  The bedding can be used to your advantage sometimes, by using the striations that are shown by the bedding or the different colors that may accompany the different beds.