I'm not in the least an expert on butter molds and the like, but I do spend a whole lot of time looking at carvings, and think I can recognize lovely things when I see them--and this, to my eye, is very much that! It's also unusual in my experience to find a number of different patterns carved in into both sides of a block as here, in an irregular configuration, almost as if practicing in advance of producing a single stamp. I take the carvings to represent a thistle, an acorn, a flower, a pineaapple, and a cornucopia, each carefully carved by hand. I am terrible identifying woods but am thinking this is maple, with a very very smooth, dense, almost silky surface.
Block measures 9" x 3 3/16" x 7/8". Very good condition, nice patina, with some small scattered round holes in the surface of the wood.