/ chawk /

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About the chemical structure:

Chemical name: calcium carbonate
Formula: CaCO3
3D model:

grey = carbon, red = oxygen, blue = calcium

Crystal system: Trigonal - Hexagonal Scalenohedral (at Mineralogy Database)
Refractive index: calcite: e =1.486, w =1.64 -1.66

How can you identify Chalk?

Chemical identification:



Raman spectra (at University College London)

UV/VIS/IR Spectra (at US Geological Survey)

Usage and handling:

Permanence: Toxicity:
excellent lightfastness, incompatible with alkali-sensitive pigments such as Prussian blue. non toxic


Artists’ Pigments. A Handbook of Their History and Characteristics, Vol. 2: A. Roy (Ed.) Oxford University Press 1993, p. 203-226

Other whites
(intro) - Calcium carbonate whites - Lead white - Titanium white - Zinc white