User:Mderrick

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Michele Derrick is the Schorr Family Associate Scientist at the Museum of Fine Arts, Boston. She was instrumental in the development of CAMEO, an online database for information on materials used in conservation and works of art (cameo.mfa.org). Prior to 1995, she worked as a scientist at the Getty Conservation Institute in Los Angeles for 12 years. A chemist by training, Michele’s expertise is in the area of infrared microspectroscopy and she is the author of Infrared Spectroscopy in Conservation Science (Los Angeles: Getty Conservation Institute, 1999). She was also the editor–in–chief of the Journal of the American Institute for Conservation from 2003-2014.


Azurite (test page)

Description

A deep blue mineral composed of bsic copper carbonate that is naturally found adjacent to the green copper carbonate mineral called malachite. Azurite and malachite have been used as gemstones and paint pigments since ancient times. They are prepared as pigments by careful selection, grinding,washing, and levigation. Coarsely ground azurite gives a deep blue color while finely ground particles give a lighter, more transparent tone. Azurite is lightfast but is sensitive to acids and sulfur fumes. Basic copper carbonate can also be made artificially by coloring chalk with copper sulfate. The synthetic pigment, called blue verditer, blue bice, Bremen blue or ashes blue, tends to have regularly sized particles with rounded edges. Their color is similar to finely ground azurite.

Synonyms and Related Terms

basic copper carbonate (natural); Pigment Blue 30; CI 77420, bleu d'Allemagne (Fr.)

File:SC52353.jpg

Other Properties

Insoluble in water, ethanol. Decomposes in acids with the evolution of carbon dioxide bubbles. Turns balck with warm alkalis, hydrogen sulfide or sulfur fumes

Stong birefringence, Highly refracting. Naturally ground pigment particles are irregular in size. Pleochroid from pale blue to deep blue.

Monoclinictabular crystals. Good cleavage in two directions

Fracture = conchoidal. Luster = vitreous to dull. Streak = blue

Hazards and Safety

Skin contact and inhalation may cause irritation or allergic reactions. Chroninc exposure may canse anemia.

Analysis

References

R. Gettens and E. West Fitzhugh, "Azurite and Blue Veridter" Artist Pigments, Vol. 2 A. Roy, ed. Oxford University Press, Oxford, 1993.