Pumice is a lightweight stone that forms when volcanic lava cools and hardens. Pumice rocks are classified as glass since they have no crystal qualities. Pumice has a variety of personal, commercial and industrial uses. You can generally find pumice in grocery stores, beauty supply shops and hardware stores.
Description
The Mineral Information Institute, or MII, explains that the word pumice comes from the Latin word "pumex," which means foam. Pumice rocks form when volcanoes erupt with lava that is full of gas. As the lava cools, the escaping gasses leave holes in the rocks. The resulting stone contains abrasive qualities. Pumice comes in various colors depending in its mineral content. Some common colors are light red, gray, brown and white.
Properties
California State Polytechnic University's Geological Sciences website reports that pumice can form from any kind of igneous rock, but most often occurs with rhyolite, basalt, dacite or andesite. Pumice contains various minerals, including zircon, feldspar and pyroxine. Pumice stones primarily form in magmas with high levels of silica.
Location
Since pumice rocks form from volcanic eruptions, these stones are primarily mined in regions with active volcanoes. While Italy produces the most pumice, Turkey, Spain, Chile and Greece also mine these rocks. Several places in the United States also produce pumice, including Oregon, California, New Mexico and Arizona.
Personal Uses
You can use pumice stones as a skin exfoliator because it has gently abrasive qualities. The Dermaxime website explains that pumice effectively removes patches of rough skin, particularly calluses and corns. Rubbing pumice on the rough skin creates fiction, causing dead skin cells to rub off and reveal smoother skin. Some facial cleansers, hand soaps and foot scrubs contain finely crushed pumice stones. Pumice's abrasive properties also makes it a useful addition to household cleansers and scouring products.
Industrial Uses
The Hess Pumice Products website reports that pumice is often used to make lightweight building materials, such as concrete, cementious grout, stucco, plaster and acoustic tile. Some electronic manufacturers use pumice to grind and polish television glass, while others use it to prepare circuit boards. Landscapers sometimes use the porous rock to condition and aerate soil. Blue jean manufacturing companies add pumice stones to their commercial washing machines to give jeans a worn, stone-washed look. Artists sometimes use pumice to carve stone and sculpt ivory.
Fun Facts
Because it is so lightweight and porous, pumice rocks float on water. According to Think Central's go.hrw.com website, pumice sometimes floats as far as 4,000 miles away from the site of the volcanic eruption. These rocks eventually become waterlogged and sink to the ocean floor. If the erupting lava hardens quickly, it typically forms obsidian instead of pumice.
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