Green soapstone is formed from large deposits of talc that occur in subduction zones, where tectonic plates rub against each other. The gradual movement of the plates causes the stone to undergo a chemical change called dynamothermal metamorphism, which re-crystallizes the chemical components of the stone, resulting in a combination of talc, chlorite, dolomite, and magnesite. The majority of soapstone used in the United States comes from Brazil, but other large deposits have been found in Finland. There are smaller, yet still commercially viable, deposits in Virginia.
Popular for centuries among sculptors, green soapstone is softer than a fingernail. Soapstone is easily cut and carved with ordinary woodworking and masonry tools, and when polished, gives off a high shine. Unfinished soapstone is a dull gray in color, and must be polished with mineral oil to bring out the green color.
Green soapstone has long been used to build fireplaces and stoves. Soapstone stoves have excellent heat retention qualities and radiate heat long after the fire is put out. Its low surface temperature makes it a safer alternative to steel, and its ability to withstand direct flame without cracking or discoloration makes it better than clay or ceramic for use in a fireplace.
Another area of use in which green soapstone has been popular for over 300 years is as a countertop surface. Early American settlers recognized the density and durability of soapstone, and incorporated it into the kitchen in many ways including countertops, sinks, and stove liners. There has been a resurgence in green soapstone countertops as an alternative to other natural stones like granite and marble. Unlike granite, soapstone will scratch if cut with a knife, but even a large scratch can be easily sanded out. Soapstone is also available in larger sheets than other stones, so larger countertops and work surfaces can be covered without unattractive seams.
Green soapstone also offers the advantage of not being slippery when wet, and is considered an ecologically safe non-slip material. Unlike other natural stones, soapstone is inert, meaning that acidic and alkaline substances will not harm it, nor will direct heat. Due to its softness, experts recommend installing supports for soapstone countertops with overhangs of more than 10 inches (25.4 cm). The only required maintenance of a soapstone countertop is periodic polishing with mineral oil. Polishing not only brings out the stone’s natural color and shine, but also conceals small scratches and evens out the wear of the countertop.