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#cochineal

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The #SciArtSeptember prompt is carmine, a bright red pigment derived from carminic acid, traditionally harvested from cochineal, a sessile parasite on Opuntia cacti in South America, north through to Mexico and the southwest US. They are laboriously collected by brushing them off the pads of prickly pear cacti. The insect makes carminic acid to deter predators but it’s precisely what attracts people,…

🧵1/n

#Carmine, also called #cochineal, is a pigment of a bright-red color obtained from the aluminium complex derived from carminic acid.

Synthetic carminic acid is complex to produce. Therefore, natural cochineal carmine is predominant on the market.

To prepare carmine, powdered scale insect bodies are boiled in an ammonia or sodium carbonate solution. #Gelatin may be added to modify the precipitation.

To obtain 1 pound of red dye, one needs 70,000 cochineal bugs.

#ThomasJefferson was, in addition to being the third U.S. president, a slaveholder, and the writer of the Declaration of Independence, an avid #chess player.

Fragments of an #ivory #barleycorn-style chess set were discovered by archeologists examining the #Monticello midden heap. The black pieces are "stained red with #cochineal, a dye commonly used in the 18th and 19th centuries which is derived from the dried bodies of females of the scale insect Dactylopius coccus." https://www.monticello.org/site/research-and-collections/chess-set-english

Jefferson's granddaughter, Ellen Wayles Coolidge, recalled that Jefferson would play marathon four hour games against his friend and ally, #JamesMadison. http://www.thehistoryblog.com/archives/9660

Image sources: monticello.org and chessantiques.com