unnamed zirconolite

Please add the REE-Nb-(Mn,Fe) rich end member of zirconolite group to the unnamed minerals. Data could be found here:
[pubs.nrc-cnrc.gc.ca]
Christof

forgotten ???

Apparently.

Not added as an unnamed species, but comment added to zirconolite page.
[www.mindat.org]

Uwe,
It should be considered an unnamed species. The normal Ca-dominant site in zirconolite is occupied: (Ca_0.321Ce_0.270REE_0.409). The total REE is greater than Ca, so it is a Ce-analog of zirconolite.

I hesitated because the three zirconolite polytypoids clearly show some homogeneity ranges, which might actually cover two or more of the five "end-member" compositions suggested in the mentioned paper. Thus, the nomenclature could become quite complicated.

I hadn't looked at the different polytypoid comps, and will do so. I don't recall a large REE content, though.

The Eifel 'zirconolite' of Della Ventura et al. (2000) is indeed a new mineral, with REE dominant on the Ca site.
Ernie Nickel mentions the Della Ventura et al. paper in his MINERAL database, but under zirconolite polytype -2M, whereas the paper clearly says that the mineral is a -3O polytype.

Williams C.T. & Platt R.G. (1993) on Mineralogical Society Spring Meeting 1993: Rare Earth Minerals: Chemistry, Origin and Ore Deposits, Extended Abstracts, 157-158 describe also a Nd-dominant zirconolite (NdZrTi2O7) from Schryburt Lake carbonatite, Canada.

[see also Coelho A.A., Cheary R.W., Smith K.L. (1997): J.Solid State Chemistry, 129, 346-359].