Protometals /(?)/

Pro·to·met·als

Protometals

n. pl.
  1. A finer form of metals, indicated by enhanced lines in their spark spectra (which are also observed in the spectra of some stars), obtained at the highest available laboratory temperatures (Lockyer); as protocalcium, protochromium, protocopper, protonickel, protosilicon, protostrontium, prototitanium, protovanadium.