Hypertufa (pronounced hyper-toofa) is the term used for a type of artificial stone. It was first created in the mid 19th century by mixing sand, peat, various volcanic aggregates and cement. It’s relatively lightweight compared to stone or concrete and no matter how cold your winter temps may be, if properly cured, is freeze proof. Hypertufa was concocted to be used as a substitute for the natural volcanic rock called Tufa. Tufa has been used for making Alpine style planting troughs.