Relationship to other species: It is a member of the hellandite group.
2002) Ciprianiite and mottanaite-(Ce), two new minerals of the hellandite group from Latium (Italy).
Hellandite forms pale pink, tabular hexagonal crystals less than 1 mm in size, with a pronounced nacreous luster.
1965) The accessory minerals from Predazzo granite (North Italy), Part III (datolite, gadolinite, hellandite, ancylite, synchisite, uraninite).
Associated minerals are: biotite, quartz, sanidine, hematite, danburite, helvite, hellandite
, allanite-(Ce) and a not yet completely characterized gadolinite-like mineral.
and vonsenite shown in Figures 2 to 4 are from two of three known localities: Km 60 Cassia and Tre Croci.