A slate clock is a mantel clock whose case is made from black slate, usually polished to a deep sheen and often decorated with incised gilt lines, coloured marble inlays or applied bronze mounts. Many were designed in a severe architectural manner, with columns, pediments and plinths that recall a classical temple or a funerary monument.
Slate clocks were made in large numbers in the second half of the nineteenth century, when black cases were fashionable for dining rooms, studies and offices. Slate offered a cheaper alternative to Belgian black marble, which it closely resembles, and the two are frequently confused. Many examples house French eight-day movements striking on a bell or gong, and some were sold with matching side ornaments as a garniture or awarded as presentation pieces with an engraved plaque. Collectors look for crisp engraving, intact edges and corners, and original gilding rather than later paint. Slate is brittle, so chips and cracks are common, and the dull grey surface of a neglected case can usually be revived with careful cleaning and a suitable wax.
