Борисов, П. А. Месторождение нефелиновых песков на Кольском полуострове / проф. П. А. Борисов. - Москва : издание Научно-технического управления ВСНХ, 1929 (Нижний Новгород : тип. "Нижполиграф"). - 64 с. : ил., черт., диагр., карт. - (Труды Института по изучению Севера / С.С.С.Р, Науч.- техн. упр. ВСНХ ; № 297 ; вып. 44).

— 63 — nepheline; a subordinate part in the rock and sands belongs to coloured minerals, — such as black aegirine, more seldom to titano-and zirkon- silicates (eudyalite of crimson and brown colour, black ramsaite, yellow- brown astrophillite and others). Feldspar and nepheline in sands as well as in the superficial product of me­ chanical weathering of the base massive—the nepheline-syenite grit and gravel, remained almost untouched by processes of chemical decomposition and their grains are fresh. Of the chemical composition of nepheline sands of the deposits in question is worth attention a high alkali content (K and Na), 11,43% to 15,86%, which is placing this kind ot mineral raw materials among rocks rich in alkali which being a source of alkali are used in glass- and china industry. A typical gross-analysis of the nepheline sand from Gr. Peschany Na- volok shows following composition: SiO, ТІО., Al.,0, Fe.,0, CaO MgO K20 Na.,0 H ,0 56,70 0,82 22,27 2,69 0,71 0,25 8,44 6,54 0,93 The reserves of nepheline sands in the deposits under consideration, in their not overgrown areas and to the depth of the ground-water level, i.-e. only to the investigated depth of 1,70-2 m, are estimated at 670.000 tons, which of course corresponds but to visible, directly accessible for working, part of true reserves, that is to say, this mumber is showing only the quantity of superficial materials of base rocks washed out by the lake wave. The practical value of this new kind of alkaline raw stuff was esta­ blished by systematic work of the State Ceramic Research Institute in Le­ ningrad in order to secure coloured glass; a series of half-industrial trials carried out by the Colonization Branch of the Murman Railway (as owner of the deposits) with co-operation of the collaborators of the Ceramic Institute, confirmed the laboratory essays. Samples with nepheline sands (as substitute for alkaline feldspar) yielded favourable resulis as to quality of china mass. Finally, the three-years essays at the marshexperiment station at the station Loukhi of the Murman Railway, are calling the attention of agronomers to a considerable growth of crop when using the nepheline sands as source for kalium manure. Analogous essays in Prof. Pr i a n i s hn i kov ’s Laboratory in the Timiriazev Agriculture Academy in Moscow also yielded favourable results. All the works regarding the investigation of deposits of nepheline sands were carried out at the expences of the Colonization Branch of the Murman Railway.