Greywacke is a common NZ stone. You can find it in our rivers, mountains and beaches. It’s actually a mixture of a few different types of stone. The wacke part of the name comes from the German word for a type of sandstone.
I like carving it every now and then. It really has a different feeling than Pounamu. Greywacke is softer in appearance and also to carve. Its neutral colors blend in instead of standing out. It is common and easy to find so is always relaxing to work with.