Cobalt blue
A sample of a commercial cobalt blue pigment
About these coordinates     Color coordinates
Hex triplet#0047AB
sRGBB (r, g, b)(0, 71, 171)
HSV (h, s, v)(215°, 100%, 67%)
CIELChuv (L, C, h)(33, 82, 259°)
ISCC–NBS descriptorVivid blue
B: Normalized to [0–255] (byte)
Cobalt blue
3D model (JSmol)
EC Number
  • 310-193-6
  • InChI=1S/2Al.Co.4O/q;;+2;;;2*-1
  • [O-][Al]=O.[O-][Al]=O.[Co+2]
Molar mass 176.892 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Cobalt blue is a blue pigment made by sintering cobalt(II) oxide with aluminium(III) oxide (alumina) at 1200 °C. Chemically, cobalt blue pigment is cobalt(II) oxide-aluminium oxide, or cobalt(II) aluminate, CoAl2O4. Cobalt blue is lighter and less intense than the (iron-cyanide based) pigment Prussian blue. It is extremely stable and historically has been used as a coloring agent in ceramics (especially Chinese porcelain), jewelry, and paint. Transparent glasses are tinted with the silica-based cobalt pigment "smalt".

Historical uses and production

Ores containing cobalt have been used since antiquity as pigments to give a blue color to porcelain and glass. Cobalt blue in impure forms had long been used in Chinese porcelain.[1] In 1742, Swedish chemist Georg Brandt showed that the blue color was due to a previously unidentified metal, cobalt. The first recorded use of cobalt blue as a color name in English was in 1777.[2] It was independently discovered as an alumina-based pigment by Louis Jacques Thénard in 1802.[3] Commercial production began in France in 1807. The leading world manufacturer of cobalt blue in the nineteenth century was Benjamin Wegner's Norwegian company Blaafarveværket ("blue colour works" in Dano-Norwegian). Germany also was famous for production of it, especially the blue colour works (Blaufarbenwerke) in the Ore Mountains of Saxony.

Cobalt glass is used decoratively, and also as an optical filter to remove or hide certain visible colors.

In human culture






Video games


Cobalt blue is toxic when ingested or inhaled. Its use requires appropriate precautions to avoid internal contamination and to prevent cobalt poisoning.

Natural occurrence

A single record of the compound concerns inclusions in sapphires from a single site.[11]

See also


  1. ^ Kerr, Rose; Wood, Nigel (2004), Science and Civilisation in China Volume 5. Part 12, Ceramic Technology, Cambridge: Cambridge University Press, pp. 658–692, ISBN 0-521-83833-9.
  2. ^ Maerz and Paul. A Dictionary of Color. New York (1930). McGraw-Hill. p. 91; Color Sample of Cobalt Blue: Page 131 Plate 34 Color Sample L7
  3. ^ Gehlen, A.F. (1803). "Ueber die Bereitung einer blauen Farbe aus Kobalt, die eben so schön ist wie Ultramarin. Vom Bürger Thenard". Neues Allgemeines Journal der Chemie, Band 2. H. Frölich. Archived from the original on 2018-02-10. German translation from Thénard, L.J. (1803), "Considérations générales sur les couleurs, suivies d'un procédé pour préparer une couleur bleue aussi belle que l'outremer" (PDF), Journal des Mines, 86: 128–136, archived (PDF) from the original on 2012-03-29.
  4. ^ "Chinese pottery: The Yuan dynasty (1206–1368)". Archived 2017-12-29 at the Wayback Machine Encyclopædia Britannica Online. Accessed 7 June 2018.
  5. ^ ""J Varley's List of Colours". The British Museum. Archived from the original on 2016-09-20. Retrieved 2016-07-22.
  6. ^ "Cobalt blue". ColourLex. Archived from the original on 2015-04-15. Retrieved 7 June 2018.
  7. ^ Cobalt Blue Is the Vibrant Shade You Need for 2023
  8. ^ "Real Salt Lake unveil new primary kit for 2018". February 8, 2018. Retrieved June 26, 2019.
  9. ^ "History". Retrieved June 26, 2019.
  10. ^ Sheffield, Brandon. "Out of the Blue: Naoto Ohshima Speaks". Gamasutra. Archived from the original on 16 July 2015. Retrieved 12 August 2013. Well, he's blue because that's Sega's more-or-less official company color
  11. ^ "UM1994-06-O:AlCo".

Further reading