iron blue

noun

1. slightly purplish or bluish dark grey

• Syn: ↑steel grey, ↑steel gray, ↑Davy's grey, ↑Davy's gray

• Hypernyms: ↑gray, ↑grayness, ↑grey, ↑greyness

2. any of various blue pigments

• Syn: ↑Prussian blue

• Hypernyms: ↑pigment

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noun

1. : steel gray

2. : any of various strongly colored pigments that range in masstone from reddish blue to jet black and possess good hiding power, that are now usually made by bringing together solutions of ferrous sulfate, ammonium sulfate, and sodium ferrocyanide and oxidizing the white precipitate formed, that consist of complex compounds regarded as both ferrocyanides and ferricyanides containing positive ions (as ammonium and sodium ions), and that are used chiefly in blueprints, inks, laundry blues, paints and enamels, crayons, and linoleum: as

a. : prussian blue

b. : turnbull's blue

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any of the class of blue pigments having a high tinting strength and ranging in shade and in coloring properties from reddish blue to jet blue: used chiefly in the manufacture of paints and printing inks.

[1690-1700]

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iron blue,

1. any one of several artificial flies of steel-blue coloration used by fishermen.

2. a blue pigment prepared from ferrocyanides, such as Prussian blue.

3. = steel blue. (Cf. ↑steel blue)