Nb-Ta-Sn-rich granitic pegmatite, 10 km SW of Tammela.
Ref.: Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 851.
Vorma, A. & Siivola, J. (1967) Sukulaite - Ta2Sn2O7 - and wodginite as inclusions in cassiterite in the granite pegmatite in Sukula, Tammela in SW Finland. Comp. Rend. Soc. Geol. Finlande, 39, 173-187.