den·ta·li·um 
(dĕn-tālē-əm)
(dĕn-tālē-əm)n. pl. den·ta·li·a (-lē-ə) or den·ta·li·ums
Any of various tusk shells of the genus Dentalium, some of which are used for ornament and were used by native peoples of western North America as currency.
[New Latin Dentālium, genus name, from dentālis, toothy; see DENTAL.]