Suprunovskoe deposit, Kazachinsko-Lensky District, Irkutsk Oblast, Russia
Muscovite-beryl pegmatite, which contains accumulations of semitransparent beryl.The beryl is mostly related to muscovite segregations in the blocky microcline at the contact with the quartz core. Some beryl crystals occur as inclusions in quartz and microcline. Large, short-columnar, semitransparent crystals up to 50 cm long are dominant. They have numerous fractures and gas-liquid inclusions. The colour is light-blue, bluish green, sometimes light-green and honey-yellow. Such crystals produce transparent areas up to 1 cm³ in volume, which are suitable for faceting. The average yield for the crystalline raw material is 1.15%.
Ref: E.Ya.Kievlenko, Geology of gems, 2003, p. 114