Description

Chert 

Occurs as oval to irregular nodules in green sand, and patches od chalcedony, where it is formed as a result of diagenesis. The brownish variety is Mn rich cherts. It is massive and was naturally smoothening

Obsidian

Rapidly cooling showimg minimum crystal growth with glistening gray. "Apache Tears" strips of rhyolitic lava flow. High silica content variety and induces high viscousity and polymerization degree of lava. Obsidian is hard and brittle and therefore fractures with very sharp edges