The Full Wiki

Sienna: Map


Wikipedia article:

Map showing all locations mentioned on Wikipedia article:

Raw sienna
Burnt sienna

Sienna is a form of limonite clay most famous in the production of oil paint pigments. Its yellow-brown colour comes from ferric oxides contained within. As a natural pigment, it (along with its chemical cousins ochre and umber) was one of the first pigments to be used by humans, and is found in many cave paintings.

Sienna, in and of itself, is sometimes referred to as "raw sienna", in order to differentiate it from "burnt sienna", which is a more common pigment than the raw form. The difference is in the process applied to create burnt sienna, which is raw sienna heated to remove the water from the clay and give it a warm reddish-brown colour.

The name derives from the most notable Renaissance location for the earth, Sienamarker, Italymarker, and is short for terra di Siena, "earth of Siena". The mines used to produce this sienna petered out in the 1940s. Much of today's sienna production is still carried out in the Italian islands of Sardinia and Sicily, while other major deposits are found in the Appalachian Mountainsmarker, where it often goes hand-in-hand with the region's iron deposits.

Many of these deposits date back to the Precambrian, and are pointed to as evidence of the Snowball Earth hypothesis.

See also


Embed code:

Got something to say? Make a comment.
Your name
Your email address