Egyptian blue is the earliest-known synthetic pigment, meaning it was not a color already found in nature (such as the precious lapis lazuli, which was mined in today’s Afghanistan). It was formed by heating quartz sand, copper, an alkali, and lime (or lime-heavy sand) into calcium copper silicate, a highly stable chemical compound. The Pigment Compendium: A Dictionary of Historical Pigments states that it was “used extensively from 4th dynasty Egypt until the end of the Roman period in Europe, as well as in certain other rare exceptions.” So after such a long use, including tomb ceilings as the night sky and the blue skin of the god Osiris, why did such an innovative hue disappear?
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.