This is the grayish-white and pinkish petalite sphere with irisation. Diameter 2.3″ (59mm). Weight – 9oz (254 grams). Origin: Russia, Transbaikalia.
Some information about petalite:
Petalite, also known as castorite, is a lithium aluminium phyllosilicate mineral LiAlSi4O10, crystallizing in the monoclinic system. Petalite is a member of the feldspathoid group. It occurs as colorless, grey, yellow, yellow grey, to white tabular crystals and columnar masses. Occurs in lithium-bearing pegmatites with spodumene, lepidolite, and tourmaline.
Discovered in 1800, by Brazilian naturalist and statesman Jose Bonifacio de Andrada e Silva. Type locality: Utö Island, Haninge, Stockholm, Sweden. The name is derived from the Greek word petalon, which means leaf (perfect cleavage).
The first important economic application for petalite was as a raw material for the glass-ceramic cooking ware CorningWare. It has been used as a raw material for ceramic glazes.