\Slat"y\, a. [From {Slate}.]
Resembling slate; having the nature, appearance, or
properties, of slate; composed of thin parallel plates,
capable of being separated by splitting; as, a slaty color or
texture.
{Slaty cleavage} (Min.), cleavage, as of rocks, into thin
   leaves or plates, like those of slate; -- applied
   especially to those cases in which the planes of cleavage
   are not parallel to the planes of stratification. It is
   now believed to be caused by the compression which the
   strata have undergone.
{Slaty gneiss} (Min.), a variety of gneiss in which the
   scales of mica or crystals of hornblende, which are
   usually minute, form thin lamin[ae], rendering the rock
   easily cleavable.