Raw sienna

Raw sienna

Description

Raw sienna at 100x (visible light left; UV light right)

A dark yellow iron oxide pigment. Raw sienna is a natural earth mixture that contains at least 50% hydrated ferric oxide (Goethite) mixed with Alumina, Clay, and some Manganese dioxide. Raw sienna is a semi-opaque, permanent pigment. It was named for the south Italian city of Siena that produced fine grades of the pigment; it was originally called Italian earth.

Synonyms and Related Terms

Pigment Brown 6; CI 77491; Italian earth; terre de Sienne (Fr.); terra di Siena (It.); Sienaerde (Deut.); siena natural (Esp.); siena natural (Port.)

FTIR (MFA)

Raman (MFA)

SEM

EDS

Physical and Chemical Properties

Density	3.14 g/ml
Refractive Index	1.87-2.17

Additional Images

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  Raw sienna at 500x
  Transmitted light

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  Raw sienna at 500x
  Polarized light

Resources and Citations

• R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966

• G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 577

• Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)

• Michael McCann, Artist Beware, Watson-Guptill Publications, New York City, 1979

• Dictionary of Building Preservation, Ward Bucher, ed., John Wiley & Sons, Inc., New York City, 1996

• Art and Architecture Thesaurus Online, https://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000