Slate — Slate shares the muted blue-gray of natural slate stone, giving it its name. It belongs to the Blue and Gray family: a dark, muted tone with hex code #516572 and RGB values of 81, 101, 114. Its dominant channel values give it a cool undertone that reads as muted rather than flat. Slate pairs well with complementary tones from the opposite side of the color wheel and works nicely in branding and logo design. Nearest neighbors: cobalt.