Blue Mountain Shale is the perfect product for rustic landscape designs. This rock has a beautiful variation of natural blues, oranges, and neutrals with a flat smooth surface. Our shale comes in a medium size ( around 2-3″ variations) or a large size (around 4-8″ variations). Medium Shale may be a bit easier to work with while still showing off all of this rock’s lively character. This rock makes for a great ground cover that is also good at helping to keep weeds down.