Ranging in size from less than 1/8" to 1/2 inch, our beautiful slate gravel substrate is sure to be a show stopper in your aquarium. Mix several sizes together for a more natural look. Use as a topper for aquarium soil in a planted tank. Smaller packages available to give an aquascaped tank a more natural look by sprinkling around your scene. Pairs beautifully with our larger slate stone and slate/quartz stone.