This specification covers two types of pigment commercially known as basic lead silicochromate. Both types of pigment shall consist of silica coated with lead licates and lead chromates with mass color and character, and oil absorption equal to that of a reference sample as agreed upon by the purchaser and seller. Specimens shall be sampled, prepared, and undergo chemical analysis to test their conformance with specified compositions of lead oxide, chromium trioxide, silica, and moisture and other volatile matter. Materials shall also be tested for ignition loss, specific surface diameter, and particle loss by microscopic methods.