Rocks of all shapes, sizes, and classifications are used in everyday life. There are three main classifications of rocks, depending on how they are formed. Sedimentary rocks are a composite of other rocks and minerals and forms when these pieces are deposited and fused together. Metamorphic rocks are formed when preexisting rocks are heated or compressed, changing their physical properties. Igneous rocks, however, are formed when molten rock- lava or magma- cools and forms crystals. The third classification, igneous, is the one I will be discussing today.
There are many types of igneous rocks that can be used in many ways. Possibly the most common, and most diverse, igneous rock is granite, a light colored rock with large crystals. Polished granite is often used in building. It makes for a durable and aesthetically pleasing building material and can be used as floor tiles, monuments, and kitchen counter tops. It was also used as building foundations in New England in the eighteenth and nineteenth centuries. In some areas, granite is also used for gravestones and memorials. A less well know use of this versatile rock is for the fashioning of curling stones. It has been used in this manner since the 1750’s. Today 60 to 70 percent of curling stones are made of Ailsa Craig granite.
Another well known igneous rock is pumice- a light colored rock with many vesicles, or pores. It is often used in healthcare/cosmetics as an additive to toothpaste, heavy-duty hand cleaners (such as Lava Soap,) cosmetic exfoliants, and pumice stones, which are often used to remove dead skin during the pedicure process. Pumice is also an additive in some concrete and in pencil erasers, and is used to produce stone-washed jeans.
Other forms of igneous rocks, such as peridotite, andesite, gabbro, rhyolite, and obsidian are polished and used to make jewelry. Diamonds can be found in peridotite in South Africa that is rich in mica. Obsidian is also used to make surgical scalpels that are many times sharper than steel blades of the same cut. Andesite can also be used to make bricks or stones for landscaping and to outline water gardens or ponds/ pools, as it is naturally slip resistant.
As you can see, igneous rocks are used in many ways in today’s society, spanning from cosmetics, to jewelry, to building, and even to the operating table. And that is just to name a few. It is hard to imagine a world without their beauty and practicality.
