Cinder Moss has been called “Holy Fieldstone" or “Lightweight Fieldstone” and is used for walls, decorative borders, and edging. This rock is sold in head size and double head size as well as complimentary boulders ranging from 100 to 3,000 lbs. Cinder Moss rock is a natural porous lava boulder with moss and lichens. Color ranges from light gray to dark gray. While it is much lighter than regular fieldstone, it can be an affordable way to build retaining walls or simple walls for landscaping décor.