Description
Catlinite, or pipestone, is a type of red metamorphic argillite found in quartzite. The mineral is quarried by Native Americans for use as pipes. The mines are located in Pipestone National Monument near Pipestone, South Dakota, and near the Pipestone River in Manitoba, Canada. The term catlinite came into use after the American painter George Catlin visited the quarries in Minnesota in 1835; however, it was Philander Prescott who first wrote about the rock in 1832, noting that evidence showed Native Americans had used the quarries since at least as far back as 1637. Minnesota catlinite is buttery smooth and can be cut with an ordinary hacksaw or even a knife. It emerges from the ground a pink color, often with a creamy coating to protect it from the hard quartzite. It is weaker and more prone to breaking under stress than Utah pipestone. Most catlinite deposits exist below the level of the groundwater or in deep enough layers where the soil is constantly moist that the iron compounds that give catlinite its red color quickly convert to iron oxide when exposed to the elements and the rocks decay and break down.
