The largest mineralized cavities are 5 m long, 1 m wide, and 2 m high (Fersman, 1962). The cavities are bordered by a coarse-grained quartz-feldspar aggregate, which grades into druses of microcline and smoky quartz with transparent beryl
, muscovite, and minor clevelandite and schorl. Near the cavities, albite and muscovite alteration of microcline is locally developed. Accessory minerals are apatite, cordierite, garnet, cassiterite, columbite, lepidolite, and other minerals.
crystals in the miarolitic cavities are often perfectly transparent with brilliant faces. Their colour is light- and wine-yellow, greenish yellow, greenish and seldom bluish-green and blue. Crystal habit ranges from short-columnar to long-prismatic and obelisk-like. Many crystals are corroded. Their length rarely exceeds 4 to 6 cm, however, the largest crystal of transparent green beryl, which was extracted in 1826 has a length of 24.5 cm. Tabular crystals of colourless or light-rose beryl
up to 3 cm long and 5 cm across were rare.
Ref: E.Ya. Kievlenko, Geology of gems, 2003, p. 108