Detailed information
Species
Bertrandite, Quartz, var. Smoky
Dimensions
50 x 62 x 30
mm
Weight
62 g
Locality
Kara-Oba Betpakdala Desert Karagandy Province, Kazakhstan
Condition
No recorded repairs
The tungsten deposit at Kara-Oba in Karagandy Province, Kazakhstan is renowned for having produced great crystals of the rare beryllium silicate Bertrandite. They are known there in several forms, one of which are the flat-topped prisms seen in this rich miniature specimen. A fan-like spray of pale Smoky Quartz crystals provides the host for many colourless to white, glassy Bertrandite crystals reaching 5 mm in length. The Quartz crystals are themselves slightly etched and have fracture surfaces on the back, but the Bertrandite crystals are very well formed and in perfect condition. This deposit closed in 1996, meaning that all specimens are likely over 30 years old. Ex the superb systematic collection assembled by brothers Martin and Michael Günther (1951-2007 & 1956-2021).