Bortolanite, a rare mineral of the rinkite group, seidozerite supergroup occurs in two different associations in the Lovozero massif in the Kola Peninsula, Russia: (1) together with ferri-katophorite and phlogopite, it forms porous or mesh aggregates (symplectitic accretions) with euhedral contours in the contact zone of a volcano–sedimentary xenolith and eudialyte lujavrite at Kuamdespakhk Mt and (2) in intergrowths with titanite and fluorcaphite in the poikilitic feldspathoid syenites at Sengischorr Mt. In both cases, bortolanite was found in association with rosenbuschite that is close to it in chemical composition, but unlike bortolanite, it contains no REEs. The mineral is triclinic, space group P$\bar{1}$, a = 9.5807(5), b = 5.6943(4), c = 7.2813(4) Å, α = 89.891(5)°, β = 100.959(4)°, γ = 101.241(5)°, V = 382.25(4) Å3 and Z = 1.

The Lovozero bortolanite differs from the Brazilian holotype sample from de Caldas alkaline massif, Minas Gerais, due to the presence of (OH)-groups in its composition, which is indicated by Raman data. A combination of single-crystal X-ray diffraction data and electron microprobe data provides the following crystal-chemical formula: (Ca1.97Ce0.01Nd0.01Th0.01)Σ2(Ca1.39Zr0.61)Σ2(Na0.72Ca0.28)Σ1(Na1.36Ca0.56Mn0.03Zn0.01)Σ1.96(Ti0.78Zr0.08Nb0.05Mg0.05Fe0.04)Σ1Si4O14((OH)0.92O0.87F0.21)Σ2F2.