Our Canyon Fossil Ecoscape rock is not only an artistic choice for the home aquarium, but also a safe choice for both fish and plants. Our Fossil Stone has no heavy metals such as pyrite. This rock is free of limestone and chalky striations. It has deep valleys and pores making it ideal for growing moss and aquascaping a planted display. It is inert and will not alter pH or hardness. It comes in a variety of shapes and sizes handpicked by the Ecoscape team to give your aquarium a unique look.