orpiment, realgar, pararealgar
Morocco
9th Century
Source: Oubelkacem, Y., Lamhasni, T., El Bakkali, A., et al. (2020). Parchments and coloring materials in two IXth century manuscripts: On-site non-invasive multi-techniques investigation. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 246, 119093.
Recipe Details
Ingredients
natural orpiment (As2S3), natural realgar (As4S4)
Preparation Steps
The yellow and orange vocalizations consist of arsenic sulfide minerals. Raman spectra identified natural orpiment (As2S3) and natural realgar (alpha-As4S4) with bands at 312, 354, and 340 cm-1 (p. 11). In MEK-MS-6LP, yellow shades were identified as pararealgar (As4S4), a degradation product of realgar, with Raman vibrations at 332 and 345 cm-1 (p. 12).
Original Recipe Text
The yellow and orange vocalizations consist of arsenic sulfide minerals. Raman spectra identified natural orpiment (As2S3) and natural realgar (alpha-As4S4) with bands at 312, 354, and 340 cm-1 (p. 11). In MEK-MS-6LP, yellow shades were identified as pararealgar (As4S4), a degradation product of realgar, with Raman vibrations at 332 and 345 cm-1 (p. 12).
Evidence
"The orange and bright yellow shades in the case of parchment MEK-MS-7LP are combinations of yellow orpiment and orange realgar at different proportions."
Remarks
Realgar and orpiment often coexist in the same geological deposits. Pararealgar results from the light-induced rupture of As-S bonds in realgar (p. 12).
Scientific Analysis
Chemical CompositionAs2S3, As4S4
Analytical Techniques
FOR
XRF
SSER
Certainty Level
Confirmed
Instrumentally Verified
Verified
Metadata
Material Type
pigment
Paper TypeParchment
ColorYellow
RegionMorocco
Approx. Year850
Source Information
AuthorOubelkacem, Y., Lamhasni, T., El Bakkali, A., et al.
CollectionMakhtout 231
Language
N/A
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