Shungite 4.34 ct.

Shungite

Shungite is elementary noncrystalline carbon with a metastable structure incapable of graphitization, it is also used as a term to describe a sequence of metamorphic rocks from the Karelia region of Russia containing such carbon. Fullerenes have been reported from such rock.
Originally desribed from Shun'ga area, Shun'ga village, Onega lake, Karelia Republic, Northern Region, Russia. ( from Mindat.org.: http://www.mindat.org/min-11040.html

There are also many others theories regarding the formation of shungite, you can check on Google about it.

Size:12x10x6.7 mm.

Weigth: 4.34 ct.

CODE#3109