Delbegetey emerald deposit, Zharma District, Abai Region, Kazakhstan
The emerald deposit is 10 km NW of the settlement of Gromovka in the Chara district, former Semipalatinsk oblast. It is related to a zone of beryl-bearing, quartz-phlogopite greisen in the exocontact of the late Paleozoic Del'begetei granite massif. Emerald mineralization has been traced within sandstones, conglomerates, and carbonaceous shales of the Lower Carboniferous Bukon'skaya suite for a distance of more than 800 m and a thickness of 15 to 20 m. Emeralds occur in two sections: Zapadnyi (Western) and Izumrudnye (Emerald).Small prismatic crystals of the bluish emerald, up to 5 mm in length, occur with light green beryl, similar to aquamarine. Larger emerald crystals up to 2 cm long are found at the Izumrudnye section in lensoid vugs of quartz greisen, in an alpite dike associated with dark blue fluorite.
Ref: E.Ya. Kievlenko (2003) Geology of gems, p. 95