Shungite is a hard, lightweight, deep black stone with a "magic" reputation that is well exploited by crystal therapists and the mineral dealers who supply them. Geologists know it as a peculiar form of carbon produced by metamorphism of crude oil. Because it has no detectable molecular structure, shungite belongs among the mineraloids. It represents one of Earth's very first oil deposits, from deep in Precambrian time.
The lands around Lake Onega, in the western Russian republic of Karelia, are underlain by rocks of Paleoproterozoic age, approximately 2 billion years old. These include the metamorphosed remains of a great petroleum province, including both the oil shale source rocks and bodies of crude oil that migrated out of the shales. Evidently once upon a time there had been a large area of brackish-water lagoons near a chain of volcanoes: the lagoons bred enormous numbers of one-celled algae and the volcanoes produced fresh nutrients for the algae and sediment that quickly buried their remains. (A similar setting is what produced the abundant oil and gas deposits of California during Neogene time.) Later in time these rocks were subjected to mild heat and pressure that rendered the oil into almost pure carbonshungite.
Shungite looks like especially hard asphalt (bitumen), but it's classified as a pyrobitumen because it does not melt. It also resembles anthracite coal. My shungite sample has a semimetallic luster, a Mohs hardness of 4, and a well-developed conchoidal fracture. Roasted over a butane lighter, it bursts into splinters and emits a faint tarry odor, but it does not easily burn.
There is a lot of misinformation circulating about shungite. It is true that the first natural occurrence of fullerenes was documented in shungite in 1992; however, this material is absent in most shungite and amounts to a few percent in the richest specimens. Shungite has been examined at the highest magnification and found to have only vague and rudimentary molecular structure. It has none of the crystallization of graphite (or, for that matter, of diamond).
Shungite has long been considered a healthful substance in Russia, where since the 1700s it's been used as a water purifier and disinfectant just as we use activated carbon today. This has given rise over the years to a host of overstated and poorly supported claims by mineral and crystal therapists; for a sample just do a search on the word "shungite." Its electrical conductivity, typical of graphite and other forms of pure carbon, has led to a popular belief that shungite can counteract the supposed harmful effects of electromagnetic radiation from things like cell phones.
A producer of bulk shungite, Carbon-Shungite Ltd., supplies industrial users for more prosaic purposes: steelmaking, water treatment, paint pigments and fillers in plastic and rubber. All of these purposes are substitutes for coke (metallurgical coal) and carbon black. The company also claims benefits in agriculture, which may be related to the intriguing properties of biochar. And it describes the use of shungite in electrically conductive concrete.
Shungite gets its name from the village of Shunga, on the shore of Lake Onega.