Synthetic ultramarine, 400x

(Photo credit: McCrone Research Institute)

Available in 1828, French ultramarine is the synthetic version of genuine ultramarine, an expensive pigment made from the semi-precious stone, lapis lazuli. Both pigments are compositionally and structurally the same but look very different under the microscope. The small, uniform particles of the synthetic version differ from the irregular, fractured particles of natural ultramarine.