Sheen Obsidian Sphere
£30.00
Sheen Obsidian Sphere, sometimes known as planet sphere - Utah
Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools without crystal growth.
Physical properties of Sheen Obsidian:
Chemical composition: 70–75% SiO2, plus MgO, Fe3O4
Hardness: 5 - 5.5
Specific gravity: 2.6
Weight: 180 g
£30.00
