tosylamide-formaldehyde resin. Thickening agents are added to maintain the sparkling particles in suspension while in the bottle. A typical thickener is stearalkonium hectorite. Thickening agents exhibit thixotropy, their solutions are viscous when still but free-flowing when agitated. This duality is convenient for easily applying the freshly shaken mixture to give a film that quickly rigidifies. Ultraviolet stabilizers resist color changes when the dry film is exposed to sunlight. A typical stabilizer is benzophenone-1. Types Base coat This type of nail polish is a clear, milky-colored, or opaque pink polish formula that is used specifically before applying nail polish to the nail. Its function is to strengthen nails, restore moisture to the nail, and help polish adhere to the nail. It prevents staining and extends the lifespan of the manicure. Some base coats are marketed as "ridge fillers", and can create a smooth surface, de-emphasizing the ridges that can appear on unbuffed nails. Some base coats, called "peel off base coats", allow the user to peel off their nail polish without using a remover. Top coat This type of nail polish is a clear colored polish formula that is used specifically after applying nail polish to the nail. It forms a hardened barrier for the nail that can prevent chipping, scratching and peeling. Many topcoats are marketed as "quick-drying." Topcoats can help the underlying colored polish dry quickly as well. It gives the polish a more finished and desired look and may help to keep the polish on longer. Gel Gel polish is a long-lasting variety of nail polish made up of a type of methacrylate polymer. It is painted on the nail similar to traditional nail polish, but does not dry. Instead it is cured under an ultraviolet lamp or ultraviolet LED. While regular nail polish formulas typically last two to seven days without chipping, gel polish can last as long as two weeks with proper application and home care. Gel polish can be more difficult to remove than regular nail polish. It is usually removed by soaking the nails in pure acetone (the solvent used in most nail polish removers) for five to fifteen minutes, depending on the formula. In fashion Traditionally, nail polish started in clear, white, red, pink, purple, and black. Nail polish can be found in a diverse variety of colors and shades. Beyond solid colors, nail polish has also developed an array of other designs,