tan·ta·lum /ˈtæntləm/

–noun Chemistry.
a gray, hard, rare, metallic element occurring in columbite and tantalite and usually associated with niobium: used, because of its resistance to corrosion by most acids, for chemical, dental, and surgical instruments and apparatus. Symbol: Ta; atomic weight: 180.948; atomic number: 73; specific gravity: 16.6.

1795–1805; < NL; named after Tantalus

Source: Dictionary.com.

The semblance of Calanctus took form on the work table: first an armature of silver and tantalum wires built upon an articulated spinal truss, then a shadowy sheathing of tentative concepts, then the skull and sensorium …

Source: Tales of the Dying Earth by Jack Vance.