Egyptian blue

From Egyptian +‎ blue, from being a blue invented by Ancient Egyptians.

Egyptian blue (countable and uncountable, plural Egyptian blues)

1. A pigment made from calcium copper tetrasilicate (“CaCuSi₄O₁₀”), the first artificial pigment, a blue, used by Egyptians for over 3 millennia, before dying out during the Roman Empire; one of the few alternates to lapis lazuli during ancient times.

• lapis lazuli
• Chinese purple / Han purple (the first artificial purple, one of the first artificial pigments)
• Chinese blue / Han blue
• Prussian blue (the first artificial pigment widely used in the modern world; not an ancient pigment)