Silicon exists in two allotropic forms, brown silicon powder and crystalline (metallic) silicon. It is the second most abundant element on earth after carbon. One of the most well known applications of silicon is in computer chip manufacture, an industry that has exploded in recent years.
Silica as sand is a vital material involved in the manufacture of glass. Another well known use is for silicone implants in the medical field, a source of some controversy. Doped with certain elements e.g boron, silicon is used in transistors, solar cells and rectifiers.
Advent Research Materials Ltd supplies Silicon in crystal and wafer form in various different quantities.