Massive coarse-crystalline aggregate of light-grey Kotoite, formed during reaction of B-bearing solutions with layer of pure magnesite. Associating minerals are black fibrous primary Ludwigite and whitish earthy alteration crust (at right) of secondary Szaibelyite. Specimen size is 6.5x4.5x2.5 cm. Collected by Nikolai N. Pertsev. Pavel M. Kartashov collection and photo.