Cobalt Powder, Color : Gray-Black

Cobalt powder (Co) is a chemical element with the symbol Co and atomic number 27. Like nickel, cobalt is found in the earth’s crust only in a combined chemical form, except for the small deposits that are found in alloys of iron natural methods. The free element, produced by reductive fusion, is a hard, shiny, silver-gray metal.

The blue pigments based on cobalt (cobalt blue) have been used since ancient times to make jewels and paintings and to give a blue note to the glass, but the alchemists thought that the color was due to the well-known metallic bismuth. Miners have long used the name of mineral kobold (German for goblin ore) for some of the minerals that produce the blue pigment; they were called because they were poor in known metals and emitted toxic fumes that contained arsenic when they melted. In 1735, it was discovered that such minerals were reducible to a new metal (the first discovered since antiquity), and this was eventually called by the kobold.