We have one at home. It’s cut from a single piece of wood. A wide dado with the
grain across the bottom to leave ~1/4” on each side for “legs”. Top is cut with
V shaped grooves leaving ~1/4” flats on each side. Grooved portion wide and long
enough to accommodate a bar of soap. I don’t know what sort of wood it is, no
remarkable grain and light in color, maple like. No discernible finish, but
maybe a wax. I can send a photo later when I get home. It does get mungy like
any soap dish, but a quick scrub with a brush cleans it up pretty quick. Haven’t
had any problems with mold.