Inorganic – Introduced at about the same time as Ultramarine, Cobalt Aluminate is a synthetic inorganic pigment. It is a more greenish-blue, with a heavier, more mineral appearance when seen as dry pigment. The hues formed from it are correspondingly heavier and greyer. But it has a certain shade that the less expensive ultramarine cannot quite match. The paint film when cured is quite soft.
| Colour Index | PB28 |
| Drying | Very Fast |
| Transparency | Semi-Transparent |
| Lightfastness | Excellent |
| Oil Content | Average |
| Tint Power | Average |
| Toxicity | Non-Toxic |
