Pocket empty ravier rectangular ceramic enamelled spirit seaside

Very beautiful pocket empty in granular ceramic (chamotted sandstone it seems to me) enamelled with three colors, an indigo blue, a brown with golden reflections and a gray white, which contrast with the simplicity of the form: a rectangle with raised corners and raw edges. It reminds me of the seaside, a rocky coast where the sea deposits its foam... It is in good condition, neither crack nor splinters: just an abrasion of the enamelling on a corner, and a small lack on the enamelling on one side but which seems to me of origin, and spots in the underside. It measures 28 cm in length by 12.5 cm in width and a maximum height of 4 cm (at a corner). It weighs 700g.