Other than an ashtray not sure what to say of this lump.
Looks deco in style, perhaps, no marks and has the colour of those old fashioned glass pavement squares - very heavy - and appears to have two fine mould seams - running diagonally opposed down from the corners of the top. Frosted underside of the top and outside of plinth - with inside of recess and top surface very shiny. Plenty of wear and couple of chips to the flanges, so could be anywhere from 1930 to 1950.
Perpahs if anyone knows a maker they might shout, and thanks for looking.