region's iron deposits. It is also still produced in the French Ardennes, in the small town of Bonne Fontaine near Ecordal. In the 20th century, pigments began to be produced using synthetic iron oxide rather than natural deposits. The labels on paint tubes indicate whether they contain natural or synthetic ingredients. PY-43 indicates natural raw sienna, while PR-102 indicates natural burnt sienna. Variations There is no single agreed standard for the colour of sienna, and the name is used today for a wide variety of hues and shades. They vary by country and colour list, and there are many proprietary variations offered by paint companies. The colour box at the top of the article shows one variation from the ISCC-NBS colour list. Raw sienna Raw sienna is a yellowish-brown natural earth pigment, composed primarily of iron oxide hydroxide. The box shows the colour of the pigment in its natural, or raw state. It contains a large quantity of iron oxide and a small quantity (about five percent) of manganese oxide. This kind of pigment is known as yellow ochre, yellow earth, limonite, or terra gialla. The pigment name for natural raw sienna from the Colour Index International, shown on the labels of oil paints, is PY-43. This box at right shows a variation of raw sienna from the Italian Ferrario 1919 colour list. Burnt sienna Burnt sienna contains a large proportion of anhydrous iron oxide. It is made by heating raw sienna, which dehydrates the iron oxide, changing it partially to haematite, giving it rich reddish-brown colour. The pigment is also known as red earth, red ochre, and terra rossa. On the Colour Index International, the pigment is known as PR-102. This version is from the Italian Ferrario 1919 colour list. The first recorded use of burnt sienna as a colour name in English was in 1853. Burnt sienna pigment (Maerz and Paul) This variation of burnt sienna is from the Maerz and Paul "A Dictionary of Color" from 1930. It is considerably lighter than most other versions of burnt sienna. It was a mix of burnt orange and raw sienna. Dark sienna (ISCC-NBS) This infobox shows the colour dark sienna. This variation is from the ISCC-NBS colour list. A similar dark sienna paint was frequently used on Bob Ross's TV show, The Joy of Painting. Sienna (X11 colour) The web colour sienna is defined by the list of X11