Minium, also known as "surik," is a vibrant red pigment with a rich history dating back to ancient times. This oxidation product of lead minerals was once mined in Spain and has been used as a pigment in paints and dyes for centuries. Although lead-based products have raised health concerns, artificially produced minium continues to be used as a pigment in various art forms.

In the classical world, red lead was used at least since the 2nd century C.E. The Romans applied the word "minium" to their native vermilion, cinnabar, and to a lesser extent, to a refined red oxide. Over time, the term "minium" was gradually more specifically applied to this mixture, and eventually to straight red lead. This pigment has been used in medieval illuminated manuscripts, giving us the word "miniature," although it's purely coincidental that these works were small.

Red lead was often used as a substitute for genuine vermilion because it was a less expensive pigment. It's made by heating litharge or white lead for several hours at a high temperature, resulting in a bright red, finely divided, and crystalline or amorphous pigment. Chemically, red lead is fairly active, but when exposed to light and air, it's not a particularly stable pigment.

In spite of its bright color and good covering power, artists do not use it much today, although it's still available. Minium is composed primarily of lead tetroxide (Pb3O4) and litharge (PbO). The greater the amount of litharge, the faster the pigment dries in oil.

Rublev Colours Red Lead (minium) is artificially made and composed of 98% red lead (lead tetroxide, Pb3O4) and 2% litharge (PbO). This pigment is best suited for oil colors or encaustic paint. It's fairly permanent when mixed with oil and has a good reputation in tempera painting. However, it's liable to discoloration in the presence of air pollutants and should not be used in watercolor painting.

When used with oil, red lead absorbs a very low amount of oil, requiring only 10% binder. It makes a very fast-drying oil paint and forms a hard, flexible film. However, utmost care should be taken when handling the dry powder pigment to avoid inhaling the dust or ingesting the pigment in any form, as it's highly toxic. Wear protective clothing and gloves to prevent contact with skin, and never use near children or pets.