Cobalt canyon in the side of a mountain. The firm Calera Mining Company started production at the site. The stable form of cobalt is produced in supernovas through the r-process. It comprises 0.0029% of the Earth's crust. Free cobalt (the native metal) is not found on Earth because of the oxygen in the atmosphere and the chlorine in the ocean. Both are abundant enough in the upper layers of the Earth's crust to prevent native metal cobalt from forming. Except as recently delivered in meteoric iron, pure cobalt in native metal form is unknown on Earth. The element has a medium
Cobalt glass cobalt oxide together with quartz and potassium carbonate. The result was an intensive blue glass-like substance that was ground and sold to producers of glassware and porcelain. "Smalt", Bruno Mühlethaler and Jean Thissen, "Studies in Conservation", Vol. 14, No. 2 (May, 1969), pp. 47–61, JSTOR Cobalt glass Cobalt glass—known as "smalt" when ground as a pigment—is a deep blue colored glass prepared by including a cobalt compound, typically cobalt oxide or cobalt carbonate, in a glass melt. Cobalt is a very intense glass colorant and very little is required to show a noticeable amount of color. Cobalt blue glass is