There are a number of uses for pumice, but some of the most common include in cleaning, in cosmetics, and in construction. The stone is lightweight, very porous, and typically has a rough exterior. When ground up it can make an excellent abrasive, and powder is often added to cleaning products designed to scrub dirt and grime away. It is sometimes added to toothpastes and certain body cleansers for the same reason, and the whole stone is often sold as an exfoliation tool that people can use to scrub away dead skin, particularly on rougher areas like the feet. In construction, the stone can add a layer of stability and cohesion to cement mixtures without adding much extra weight. Farmers and gardeners often use it as a growing substrate, too, as it can help improve soil quality without impeding root growth; its porous quality means it can also serve as a base for hydroponic growing, which is to say, plants grown in water but no soil. In some places the stone also has some uses within the pet care industry, particularly as a chewing device for small rodents like gerbils and guinea pigs. It can keep their teeth filed and is often thought to be pleasurable for these animals to chew.
The stone is a natural lava-based substance that is expelled from volcanoes. When a volcano erupts, the lava it spews out is very hot, and it rapidly cools when it is exposed to the colder air outside. This rapid cooling transforms the foamy lava into pumice. It typically has a glassy finish and abrasive texture, and an almost pockmarked appearance left from the tiny bubbles in the lava. The bubbles basically leave air pockets, which makes the final product strong but also incredibly lightweight. It is one of the only types of stone that floats.
There are a number of reasons that what is essentially hardened lava has found popular use as a consumer material. As volcanic activity happens globally, it is naturally produced in many countries. It often doesn't require extensive processing, so it can be a cost-effective alternative to other products. It also offers a number of unique qualities that are valued by different industries.
As a Cleaning Abrasive
One of the main qualities of pumice is that it is abrasive. This abrasiveness makes it valuable in applications that require a scrubbing substance. For example, some natural household cleaners include powder ground from the stone as one of the primary ingredients to help scour stains from appliances, floors, and other surfaces. Some toothpastes use it, too, though in smaller amounts; it can help remove plaque from the surface of teeth, but isn’t usually intended to be swallowed. Since the stone is a naturally-occurring substance, using it instead of more chemically-based cleaners can have environmental benefits and can also appeal to consumers looking for “green” cleaners for home and body.
Many different body scrubs and dead skin removers also rely on this natural element, either as a whole stone or ground into powder. Whole stones are often formed into bars or other contoured shapes to allow ease of use when scrubbing the feet and other rough areas of the body. In cleansers, powder is often added to soaps or scrubs to give them more grit and resistance. One cosmetic application that isn’t common is in lotions; the roughness of the stone means that it shouldn’t stay in contact with the skin for very long, and it can actually dry the skin out and cause itchiness if left on for too long.
Additionally, the lightweight quality of the stone makes it useful in some aspects of construction. When incorporated into concrete, plaster or other construction materials, the finished product can substantially lighter than other mixtures while retaining the same strength. As it is naturally occurring and can be found around a number of volcanic sites worldwide, the stone can also be more cost-effective than many other construction materials.
When ground, this lava product is commonly added to soil on new farms or gardening plots in order to improve overall quality and to help roots take hold. It can also help water distribution and retention in the ground. In some places it’s also used on hydroponic farms as a way of sustaining and supporting the roots of plants grown without soil, usually in greenhouses or in other special constructions.
There is sometimes also a demand for the stone in the pet care industry. Small domestic animals often chew on bricks of it to help keep their teeth clean and filed; this is most common where things like chinchillas, gerbils, and guinea pigs are concerned. Pumice chew toys aren’t usually recommended for larger animals like dogs and cats, since the strength of these animals’ jaws can break or crumble the stone.