Degraded realgar
Iraq
9th Century
Source: Marotta, G., Fedeli, A., Sathiyamani, S., & Colini, C. (2025). Archaeometric philology for the study of deteriorated and overlapping layers of ink: the colour code of an early Qur’anic fragment. Eur. Phys. J. Plus, 140, 446.
Recipe Details
Ingredients
realgar, arsenic sulphide, pararealgar
Preparation Steps
Historical recipes for yellow inks using realgar are found in the works of al-Marrākushī (Section 5, p. 9).
Original Recipe Text
Historical recipes for yellow inks using realgar are found in the works of al-Marrākushī (Section 5, p. 9).
Evidence
"When analysing the yellow pigments with Raman spectroscopy, we observed the peaks at 353 cm−1, 189 cm−1, 220 cm−1 and 244 cm−1, characteristic of realgar, an unstable form of arsenic sulphide (As4S4)... Peaks at 231 cm−1 and 155 cm−1 could be attributed to pararealgar, which is yellow in colour."
Remarks
Used to mark second-level variants (p. 13). The yellow pigment suffered photo-oxidation, transforming the original orange realgar into yellow pararealgar (Section 4.2). Mercury is present as a trace contamination (p. 4).
Scientific Analysis
Chemical CompositionAs4S4
Analytical Techniques
XRF
Raman spectrometer
Certainty Level
Confirmed
Instrumentally Verified
Verified
Metadata
Material Type
pigment
ColorYellow
RegionIraq
Approx. Year850
Source Information
AuthorMarotta, G., Fedeli, A., Sathiyamani, S., & Colini, C.
Collectionf. 4r, f. 10r, f. 10v
Language
N/A
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