There are a number of recipes for hypertufa. The basic one is sand or perlite combined with cement and peat moss. The finished products are lighter in weight than concrete and have an ancient look about them, as if they'd been sitting outside for the past couple of hundred years or so just waiting for you to find them and fill them with sedum or hen and chicks or rare alpines or even shade-loving plants, if that's your choice for wherever you garden.