Turnbull’s blue

pigment

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Last updated

July 14, 2026

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Turnbull's blue is an iron blue pigment with a coppery luster. It is formed when an alkali metal ferricyanide and a ferrous salt are combined in a solution. This pigment is chemically similar to Prussian blue, another iron blue pigment. Both are composed of complex iron cyanides. Prussian blue was first synthesized around 1704 and its color arises from electron transfer between iron ions. Turnbull's blue was formerly thought to be ferrous ferricyanide.12

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Prussian blue
Turnbull’s blue, formed by the reaction of ferricyanides and ferrous salts, has the same chemical composition as the iron blues (MFe₂[CN]₆, in which M represents an ion such as sodium or potassium).
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Turnbull’s blue, formed by the reaction of ferricyanides and ferrous salts, has the same chemical composition as the iron blues (MFe₂[CN]₆, in which M represents an ion such as sodium or potassium).
Read More