Shungite

Elite shungite is a natural healer and energy stabilizer. 
Shungite elite contains around 98% carbon and carbon-fullerene, is extremely rare, and is characterized by a semi-metallic appearance. In fact, it is black-silver in color and is lightweight. It is the most valuable,  and is also called silver, crystalline or meteoritic quality. Unfortunately, it is a layered stone, so it cannot be worked.