vesbium

from The Century Dictionary.

• noun A supposed new chemical element announced in 1879 by Scacchi as present in lava from Vesuvius. It was afterward shown to be vanadium.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Chem.) A rare metallic element of which little is known. It is said by Scacchi to have been extracted from a yellowish incrustation from the cracks of a Vesuvian lava erupted in 1631.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun chemistry, obsolete A supposed rare metallic element extracted from Vesuvian lava, of uncertain composition.