1. The chemical composition of kolovratite is characterized by a wide spectrum of elements. Mineral changes from Al-Zn-Ni-silicate with a low content of vanadium to Al-V-vanadate with a low content of Si, Zn, Ni. Such perfection of the element interchangeability is possible only in the complex, loose, layered structure.
2. The relationship between vanadium and silicon, which occupy tetrahedral position in the structure, is especially demonstrative in kolovratite. Octahedral elements (Zn, Ni and Cu (to a smaller degree)) not only interchange one another, but are depended on aluminium content. This permits to distinguish to varieties of kolovratite: zinc-bearing (Karatau type) and aluminium-bearing (predominantly, Fergana type (1, 2)).
3. The general formula of kolovratite is: (Zn,Ni,Cu)$_{2-5}$ Al$_{4-6}$ [Si$_{4-n}$ (V$^{4+}$V$^{5+})_{n}$](O$_{20-q}$ OH$_{2q}$).p H$_{2}$O, where p= 7.5-11.5, water is in the metacolloid state. It is complicated for specimens rich in vanadium: (Zn,Ni,Cu)$_{1-4}$ Al$_{3.5-5.5}$(V$^{4+}$V^{5+})_{m}$ [Si$_{4-(n-m)}$(V$^{4+}$V$^{5+})_{n-m}]_{4}$ (O$_{20-q}$ OH$_{2q}$).p H$_{2}$O, where p= 10-17.2
4. The refined unit cell parameters of Karatau's kolovratite with a low vanadium content on XRPD data are: a = 5.16(1)Å b = 9.146(7) Å c = 11.98(7) Å $\beta = 97.3(5)^{o}$.
1. Vernadsky V.I.: Dokl.Russian Akad.Nauk. A.(1922) 37
2. Jambor J.L., Lachance G.R. : Can.Miner. 7. 2.(1962) 311-314