Soapstone, undetermined age, undetermined provenance. This sample is a pyritic soapstone - the small, dark-colored patches are pyrite crystals. The light-colored, curvilinear structures are veins.
This is the oddest decorative stone lithology. Soapstone is a talcose, generally crystalline-textured, metamorphic rock. Most soapstones form by metamorphic alteration of serpentinites. Being composed of talc, this rock has a hardness of 1 on the Mohs Hardness Scale, and is easily scratched. So I wonder what good is it as a decorative stone? (I honestly don’t know.)