Hearth rugs are small, fire-resistant rugs used to protect the floor and carpeting in front of a fireplace. The word hearth refers traditionally to brick or stone fireplaces that were used for cooking and heating.
Hearth and Fireplace, Hearth and Home
Though the phrase "fireplace rugs" would seem more direct to a modern person, "hearth rugs" has remained the preferred term due to the hearth's treasured place in familial history. No better proof of this is available than the idiom "hearth and home," which equates the home fire with family, cooking, warmth, and comfort.
Historically, a hearth was so synonymous with family that a hearth tax was used in 17th century England. As the number of hearths was roughly equal to the size of a house, the hearth tax worked much like a property tax.
In homes with dirt-packed floors, hearth rugs were unnecessary. But as carpeting became more commonplace, hearth rugs made from wool and other materials were required to guard against errant sparks. Chances are if you read a classic 19th century author such as Charles Dickens, Anthony Trollope, or even Lewis Carroll, you're going to find a hearth rug entering the story somewhere along the way.
Modern Hearth Rugs
Today, hearth rugs are made from a variety of materials, but nylon, wool, and fiberglass are the most common. Nylon hearth rugs are cheap and mostly decorative rather than protective. Wool fireplace hearth rugs won't melt like synthetic materials and wool is a very strong and long-lasting fiber. But the utmost protection is provided by fiberglass hearth rugs. Fiberglass fireplace rugs won't burn or melt, and any black marks left by sparks can be washed out easily.