Shungite octahedron 4 cm

Platonic solids or geometric polyhedrons consisting of regular polygons. 

 Such polyhedrons have been known since ancient times and are characteristic of Plato's philosophy, in whose honor they were named "Platonic solids". Plato wrote about them in his treatise Timaeus (360 B.C.) where he compared each of four elements (earth, air, water and fire) to certain correct polyhedron. 

 The octahedron made of shungite is a regular polyhedron with eight faces. The octahedron symbolizes the element air