A spiral drill bit tipped with tungsten-carbide hard metal, selected according to the type of stone being drilled.
Punta widia is a spiral drill bit with a hard-metal tip used for drilling stone. Le voci del marmo notes that the characteristics of the Widia tip vary according to the stone being drilled.
Etymology
Widia is a trade-derived term from German wie Diamant, “like diamond,” used for tungsten-carbide hard metal.
Sculptor Notes
The important point for the sculptor is material matching. A bit that performs well in one stone may cut poorly, overheat, wander, or wear rapidly in another.
References
https://levocidelmarmo.sns.it/scheda_oggetti_relazione.php?denom=punta+widia&id=51