of a purplish black colour.

(nautical) a slate on which the courses steered by a ship (and distances run) were recorded, but have been wiped clean after being entered in the log at the end of a watch / (by extension) a fresh start

(mineralogy) A rock formed by contact metamorphism of carbonaceous shale, characterized by prominent cleavage or schistosity and the presence of conspicuous chiastolite crystals in a fine-grained groundmass.

plural of chiastolite slate

A soft, slaty substance used in crayon drawing.

(mineralogy) A variety of slate used for sharpening cutting instruments; novaculite; oilstone.

A gray siliceous stone.

Alternative form of slate gray

plural of blank slate

Used other than figuratively or idiomatically: see blank, slate. / (figuratively) Something that is clear and empty, or free from preconceptions and biases.