Sitsinskii

This symmetrically shaped intrusion, with an area of about 25 km2, is formed predominantly of aegirine-riebeckite granites.
In the outer parts of the intrusion the rocks are intensively albitized and alkaline pegmatites are present, while throughout there are numerous veins of grorudite and solvsbergite. The alkaline granites are formed of quartz (15-40%) and mainly perthitic K-feldspar with 20-25% of dark coloured minerals, predominantly riebeckite and aegirine. Accessory minerals are aenigmatite, astrophyllite, titanomagnetite, zircon, xenotime, chevkinite and bastnaesite.