a. 石板一样的, 石板色的

[ adj ]
of the color of slate or granite
<adj.all>
the slaty sky of dawn

Slaty \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.