Soapstone, also called soaprock or steatite, is a type of metamorphic rock that consists mainly of talc. It is soft and has a soapy feeling surface, and it has been used as a carving medium around the world for thousands of years. Soapstone is also sometimes used to make molds to cast soft metals, like silver and pewter.
Metamorphic rock is one of the three main rock types in geology, along with igneous rock and sedimentary rock. Metamorphic rock is the result of the effects of great heat and pressure upon another rock type, called the protolith. In the case of soapstone, high pressures at the boundaries of the tectonic plates making up the earth's surface transform protoliths including dunite, serpentinite, and dolostone into metamorphic rock. Soaprock is high in magnesium and has varying amounts of other minerals.
Soapstone has many properties that make it desirable for carving, including its softness, which makes it easy to work with. Soapstone is also resistant to heat, making it a good choice for fireplaces, wood stoves, cookware, and pipes. Today, soaprock is most often used in kitchens, especially for countertops. In Alaska and Scandinavia, it is also popular in fireplaces and wood stoves.
Soapstone's smooth surface makes it ideal for casting metal because the finished product does not stick to the mold. In addition, the hot molten metal will not damage the mold due to its heat resistance. Soapstone is also used by tailors and carpenters, as it can be used to make very visible marks that wash off easily.
Soaprock may come in a variety of colors, based on its mineral content. Over time, it will develop a patina. Often, when soapstone is used in kitchen furnishings, mineral oil is applied in order to darken the stone. The mineral oil does not protect the stone, but simply enhances its color.
Soaprock has been in use as a carving medium since ancient times. It was widely used by many Native American groups, as well as in the Middle East, the Mediterranean, Africa, and South Asia. Beads, amulets, and seals made of soaprock have been discovered at the archaeological sites of many ancient cultures. In medieval India, soaprock was used to build large temples. The stone has also been used for tombs and furniture.