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  • Writer's pictureMichael Skalka

Cave Dust and Gold – Realgar and Orpiment

Summary: Old pigments contain a glimpse into the history of what was mined or harvested materials, the chemical makeup of these materials, and the trades that offered these colorants to artists for their use. The topic of this essay is the long-discontinued colors Realgar and Orpiment.


If you become bored looking at websites displaying modern pigments available today, you can venture back in time by finding old catalogs to explore pigments that contain true elements of danger.  While there are many, this essay will focus on two related pigments that would have been known and used in ancient Egypt and continue to appear centuries later, and in the case of orpiment, was included in catalogs up to the late 19th century. (Sartorius, 1891) 



While the Greeks referred to orpiment by the name arsenikon because of a belief that metals had gender identities, the Persian term zarnikh more aptly is derived from the word zar which means gold. Realgar is of the same chemical composition and its name comes from the Arabic, rahj al ghar which means “powder of the mine” (Artists’Pigments, Vol. 3 1997, Elizabeth West Fitzhugh) Realgar was humorously referred to on the Internet as “Mine Dust.”


The core chemical composition of both Realgar and Orpiment is Arsenic Sulfide  AS2S3.  One does not need to hold a degree in chemistry to realize that anything containing arsenic has a high degree of danger associated with it. (See the Syntax of Color essay: Bodies in the Cellar or The Old and the Forgotten.


A question about unusual or toxic colorants comes to mind when exploring old pigments.  “Why did art materials manufacturers use highly toxic materials to make colorants for artists?”  The answer is a mixture of practicality related to the date, how materials were both sourced and distributed, and the application of technology, or lack thereof, that influenced what colors could be provided to artists.


Overall, when a somewhat easy-to-obtain material is already the color desired and the technology or a company/independent scientist/inventor is not actively seeking to create that particular color, the availability of “ready-made” material fills the gap until someone or some scientific discovery or breakthrough opens a new road to producing a colorant. In some instances, a material is so outrageously toxic but the color is desirable and an ambitious inventor comes to the rescue to create a less dangerous substitute.  With voids in scientific advancement, the desire to provide an addition to the palettes of colors tends to ignore much of the inherent danger that may be a characteristic of a colorant. In most cases, science is the driving force that produces relatively safe new materials for artists. History is riddled with ignorance of the danger many materials pose.


The world of pigments has always been melded with the ancient pharmaceutical–chemical domain.  An apothecary was the source of medicines, art materials, and other domestic products that had chemical origins.  So the presence of arsenic sulfide in an apothecary would not have raised any cause for concern.  Arsenic sulfide was one of a host of dangerous materials sold to the public.  Arsenic sulfide was used for medicinal purposes, even though it was known to be poisonous. Further, it was also used for military weaponry because of its harmful properties.  (It is like the old joke – “it’s a furniture polish as well as a dessert topping.”) 


To make matters more confusing, raw materials purchased by paint makers gave the same colorant different names despite the colors possessing the same chemical composition.  Orpiment appears to be called a variety of names that include King’s Yellow (synthetic orpiment) Chinese Yellow, and of course, Orpiment. The names of colors of the same chemical composition can be driven by the origin of a material, or in many cases, by zealous marketing directors attempting to capture an alluring, exotic reference. For a “master class” in color naming visit a paint store and behold the dazzling, mind-numbing array of names that adorn all of the color sample cards that are neatly arranged by hue families in the racks.


Realgar appears to only be called by one name.  However, in my opinion, I suspect that several red-orange colors listed in catalogs may have arsenic sulfide foundations. Supporting this notion is that several terms listed in the Cameo Materials Database refer to Realgar as Red Arsenic Sulfide, Arsenic Orange, Red Orpiment, Burnt Orpiment, and Ruby Sulfur.  As indicated, artists appeared to not be horrified by pigment names that reek of dangerous toxic ingredients.  Artists in the past were either fearless or extremely ignorant.


Natural mineral examples of Orpiment and Realgar display that they coexist in the same geological space. While samples found on mineralogical websites display pure instances of yellow rocks that look like the pigment Orpiment, other samples show a mixture of yellow and deep orange.  This likely accounts for paint names that have a range of deep yellow to yellow-orange hues based on the homogeneity of concentrations of yellow or orange in the minerals used to make a pigment.


This essay was written to inform you about the history of these colors, not to encourage you to seek out sources of Orpiment or Realgar and make your own paint.  First, the substances are HIGHLY toxic and require sophisticated safety precautions to handle them.  These measures are far more than any art studio is equipped to handle. Second, other colors that are safe to use provide the same hues.  Third, Orpiment and Realgar are highly reactive with other pigments and are both fugitive, moisture sensitive and display degradation over time.  Needless to say, Orpiment and Realgar never made it to the coveted Winsor and Newton “Select List” of pigments that the company assured its customers would be lightfast, stable, and non-reactive with other colors.


Focusing on the time before 1800:  Many colors have disappeared over the ages and Orpiment provides a good example of how the desire to add a yellow color that was warm and earthy with adequate tinting strength kept it in use.  Until the appearance of chrome yellows and later cadmium colors, yellows were confined to earth pigments like Yellow Ochres, Patent Yellow, (lead chloride oxide) the very cool and opaque Naples Yellow, (lead antimonate) Lemon Yellow, (strontium or zinc chromate), and Yellow Lake, (an oak bark extraction – Quercitron).  The pigments listed above are a weak lineup of colors in the family belonging to an important primary hue.


Realgar provided a much-needed orange hue for color choices.  Pigments resembling orange were materials like Madder (manipulated to display an orange-like hue rather than crimson red or brown) Mars Orange (a metal oxide) and finally, a natural Vermillion that displayed more orange rather than red characteristics.

Take heart that our paintboxes do not have to be a toxic nightmare of deadly substances.  Artists can choose colors that span a broad range of toxicological concerns. 


Bear in mind that all pigments have potential hazards and cannot be treated with reckless abandon.  While many artists are voicing concerns about using cadmium pigments, those concerns can be addressed by responsible, safe handling and disposal of the paints in question. Unless an artist practices very sloppy studio habits that would cause paints to be ingested or introduced into broken skin, safe practices minimize most problems that might arise.  The same holds for a substance like gasoline. If we refrain from doing something idiotic like drinking it or using it as a solvent for cleaning brushes, hands, and clothing, it remains in our car’s fuel tank safely isolated from doing any direct harm to us.


To see some examples of Orpiment and Realgar, examine many of the works of art by Jean-Baptiste Simeon Chardin found a multitude of museums. 


I am looking forward to exploring a range of topics on pigment history, techniques, new materials, and studio practices as we enter the new year, 2024.


The Syntax of Color


Postscript: Special thanks to the late Elizabeth West Fitzhugh. We spent time together when she served as editor for Volume 3 of Artists’ Pigments, A Handbook of Their History and Characteristics.  We discussed several logistical and administrative aspects of author essays that make up the contents of Volume 3. I tried as best I could to alleviate her deadline worries and tardy submissions by a host of authors who contributed to the book.  Working with Liz was a huge shift in responsibilities that contrasted with the first round of editing and conformance to stylistic rules that I experienced when working with Ashok Roy on Volume 2 Artists’ Pigments, A Handbook of Their History and Characteristics of the Pigment Series.  In the case of Volume 3, the authors were all living.  The authors of Volume 2 were all deceased since the book was to be a compilation of essays from the periodical Studies in Conservation. Overall, the work fostered my deep love of pigments and the history associated with them.

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