Ray Lopez

Cobalt: More Than Just Blue

You forgot one other essential property of cobalt: it used to be used in beer. From a scientific paper of 1965:
Synopsis:
Cobalt is present in trace amounts in virtually all living tissues. The rawmaterials used for brewing-barley, corn, rice, and hops-are no exception. As a consequence, commercial beer normally contains a minute concentration of cobaltous ion, usually a few hundredths of a part per million. Such trace amounts of cobalt are of no consequence to the properties of beer, and brewers have, until recently, had no particular reason, other than scientific curiosity, for analyzing beer for its cobalt content. Although a number of assay procedures have been available for the quantitative estimation of low concentrations of cobalt in various materials, these had not generally been applied to beer.

This situation was changed by Thorne and Helm's discovery that the addition of cobaltous salts to beer to give about 1 ppm. cobalt is beneficial, improving foam properties and inhibiting gushing.