Rublev Colours Pigment Ambrogio Yellow Earth - 4 oz

Ambrogio Yellow Earth is a natural earth containing clay tinted by hydrated iron oxide and is composed of goethite and traces of clay, gypsum or manganese carbonate. It comes from quarries located near Sant'Ambrogio di Valpolicella, a municipality in the northern Italian province of Verona in the region of Veneto.

Historically, yellow earth was designated by the mineral name limonite. Limonite, however, is not a true mineral, but a general term used to describe all forms of hydrated iron oxide minerals (α-FeOOH) that occur as natural earth. Limonite includes the minerals goethite, akaganeite and lepidocrocite. The names for yellow iron oxide pigments are confusing. The names earth and ocher are suitable when it is clear that the pigment comes from a natural source. Earth is a more general term, since ocher refers to a specific type of iron oxide deposit containing kaolin (clay) and quartz. To be considered an ocher, for example, the content of iron oxide must not be less than 12%. Depending upon the content of hydrated iron oxide, the color of ocher varies from light yellow to orange-red. Like red iron oxides (hematite), they are found around the world and have been used as pigments since prehistory. French ocher, historically one of the best grades of limonite, contains about 20% iron oxide and is high in silica.

WARNING: Exercise care when using dry pigments. Do not eat, drink or smoke. Avoid breathing dust. Use a NIOSH-certified dust respirator. Wash hands immediately after use. If the creation of dust is likely, wear protective clothing.