Lomonosovite

[3] The main admixtures are niobium (up to 11.8% Nb2O5), manganese (up to 4.5 %MnO) and iron (up to 2.8%).

Named for Mikhail Lomonosov – famous Russian poet, chemist and philosopher, but the earlier – mining engineer.

[4] The crystal structure of lomonosovite is based on three-layer HOH packets consisting of a central octahedral O layer and two outer heteropolyhedral H layers.

Ti- and Na centered octahedra are distinguished in the O layer, whereas the H layers are composed of Ti-centered octahedra and Si2O7 diorthogroups, (like in other heterophyllosilicates, for example lamprophyllite).

[7] Lomonosovite forms lamellar and tabular crystals with perfect cleavage.

[3] Accessory mineral of peralkaline agpaitic nepheline syenites (like Khibina and Lovozero massif, Russia, Ilimaussaq intrusion, Greenland) important mineral of agpaitic pegmatites and peralkaline fenites.