Almost all countries follow variations of the RIAA certification categories, which are named after the precious materials gold, platinum and diamond silver is also used in some countries. The number of sales required for these awards varies depending on the population of the territory in which the album is released. Normally they are awarded only to albums released at least nationally and are awarded individually for each country in which the album is sold. Additionally, different sales levels may exist for different music media, such as albums, singles, or videos.