Egyptian Blue (Latin: caeruleum)

 These images are ochre's chemical structure, a sample of the raw material and an example of its use from the museums's collection.

• Egyptian blue is a much older technology than glass, first used ~3,000 BCE.
• The rectangular blue crystals contain 64% silica, 15% calcium oxide, 21% copper oxide, together with unreacted quartz and some glass.
• The pigment colors a variety of different media such as stone, wood, plaster, papyrus, and canvas, making cylinder seals, beads, scarabs, inlays, pots, and statuettes.

These blogs were inspired by a 2017 show at the Indianapolis Museum of Art called CSI: Chemistry of Color