All varieties of obsidian can be used as grounding and protective agents. The snowflake obsidian helps people surrender or let go of negative habits or past pathways that no longer serve their present condition. It can bring about the opportunity for change, serenity, and clarity.
Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock.
It is produced when felsic lava extruded from a volcano cools rapidly with minimal crystal growth.
Obsidian is commonly found within the margins of rhyolitic lava flows known as obsidian flows, where the chemical composition (high silica content) induces a high viscosity and polymerization degree of the lava. The inhibition of atomic diffusion through this highly viscous and polymerized lava explains the lack of crystal growth.
Obsidian is hard and brittle; it, therefore, fractures with very sharp edges, which were used in the past in cutting and piercing tools, and it has been used experimentally as surgical scalpel blades.
Read more here: https://en.wikipedia.org/wiki/Obsidian