A soft talc-rich rock. Soapstones are rocks composed of serpentine, talc, and carbonates (magnesite, dolomite, or calcite). They represent original peridotites which were altered at low temperatures by hydrothermal solutions containing silicon dioxide, SiO₂; carbon dioxide, CO₂; and other dissolved materials (products of low-grade metasomatism). Among the rock products thus formed are antigorite schists, actinolite-talc schists, and talc-carbonate rocks. To the last belongs the true soapstone, but the whole group of rocks may loosely be referred to as soapstones because of their soft, soapy consistency. Such rocks were selected by prehistoric humans for making primitive vessels and pots, and for making rough carvings for ornamental purposes.