Prussian blue

American  

noun

1. a moderate to deep greenish blue.

2. one of the iron blues, a dark-blue, crystalline, water-insoluble pigment, Fe 4 [Fe(CN) 6 ] 3 , produced by reacting ferrocyanic acid or a ferrocyanide with a ferric compound: used in painting, fabric printing, and laundry bluing.

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Prussian blue British  

noun

1. any of a number of blue pigments containing ferrocyanide or ferricyanide complexes

2. 1. the blue or deep greenish-blue colour of this pigment

   2. ( as adjective )

      a Prussian-blue carpet

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Etymology

Origin of Prussian blue

1715–25; translation of French bleu de Prusse, so called because it was discovered and first reported in Berlin, capital of Prussia

Example Sentences

I imagined a vitrine of the pigments used to achieve those “Gainsborough blues”—indigo, Prussian blue, ultramarine, azurite.

From The Wall Street Journal • Mar. 4, 2026

You know the print: swoops of Prussian blue water topped with white foam curling like fingers above the abyss, Mount Fuji in the back.

From Seattle Times • Sep. 7, 2023

Although I'm much more accustomed to sticking to neutrals, I've learned I shouldn't fear an emerald green or Prussian blue.

From Salon • Jul. 31, 2022

"There were just four stamps printed, and then there was a mistake and they printed several sheets in the wrong colour - Prussian blue - and they are very rare and very expensive."

From BBC • May 31, 2022

So he asks Theo to send him his colors: silver, white, lemon chrome yellow, vermilion, geranium lake, carmine, Prussian blue, very light cinnabar green, orange lead, emerald green, and more.

From "Vincent and Theo: The Van Gogh Brothers" by Deborah Heiligman