Obsidian is a naturally-occurring volcanic glass and is probably one of the most widely recognized rocks or minerals. The name obsidian is one of the most ancient of rock names still in use today and was brought into the language by Pliny (the Elder) almost two millenia ago. Iddings (1888:261) writes that the stone was named after "...Opsius, its discoverer, in Ethiopia, according to Pliny, who says that when laid in chamber walls in the form of mirrors it reflects shadows instead of images."
The term obsidian is a textural one and the chemical composition of the glass can vary from basaltic to rhyolitic. Since the obsidians of varying compositions are often megascopically indistinguishable, they are all lumped into this one category. If the composition is known, however, the term obsidian should be preceded by the appropriate rock name as defined by silica content, i.e. basaltic, andesitic, dacitic or rhyolitic. Though the composition of obsidians is variable, the vast majority are rhyolitic in composition, the reason for this being related to the high viscosity of high-silica melts.
All varieties of obsidian are good utilized as grounding and protective agents - The snowflake in particular helps us surrender or let go of negative habits or past pathways that no longer the present condition. It will bring about opportunity for change, serenity, and clarity.