Nov 16 Antique Black & Gold Seth Thomas 1800’s Slate Mantle Clock. Runs Nice POSTED BY admin IN antique A great looking Seth Thomas mantle clock, looks to be made from black slate or a type of black stone with faux marble highlights. The clock is 12″ H x 15 3/4″ wide x 6 1/2 deep. The clock is a heavy 27lbs. Tags : 1800's | antique | black | clock | gold | mantle | nice | runs | seth | slate | thomas