I purchased a bunch of these individually made and featuring different patterns when I was recently in Sorrento Italy on a sourcing trip. These are 18th to early 19th Century butter molds made by monks. They are made of earthenware or stoneware pottery material. Nubby feet and this one features a large impressed guitar musical instrument.  This is 4" by 6" wide and about 1.5" deep. See images showing few sections on the rims with missed glaze. These can be used for hanging, soap dish etc. So many great uses! Catch all trinket holder etc. Knowing they were made by monks and sourced in Sorrento Italy at a lovely antique store just warms my heart!