Horsetail (Equisetum arvense) is among the oldest of all plants, having dominated the plant world for 100 million years. In ancient times, it was a giant fernlike tree. The twenty species surviving today are miniature versions of their ancestors. Horsetail is known for its abrasive texture. In fact, Horsetail can be used to sand wood or scour and shine metal. This remarkable quality is due to its high silica content. Silica, a vital element of health, is found in all tissues and organs of the body, including the skin, hair, nails, teeth, bones, tendons and ligaments. Horsetail yields a deep green color when used for dying fabric. The cut stems also make an interesting addition to herb and flower arrangements.