| Cobalt blue | |
|---|---|
 A sample of a commercial cobalt blue pigment | |
 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°) |
| Source | [Unsourced] |
| ISCC–NBS descriptor | Vivid blue |
| B: Normalized to [0–255] (byte) | |
| Identifiers | |
|---|---|
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.100.107 |
| EC Number |
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PubChem CID
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| Properties | |
| Al2CoO4 | |
| 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).
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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".