The next question that arises is more perplexing, if the crystal like structure observed in the obsidian is the result of a natural casting process that took place during a period volcanic activity in the San Bernardino Valley, what was the original positive that gave rise to the cast into which the molten obsidian migrated and filled. The octahedral nature of the facets combined with the tabular layering found in a volcanic setting could be any number of minerals. For example Pyrite or Spinel are both octahedral, but a diamond would also be nice. Though I doubt the magma pipe goes deep enough to reach the temperatures and pressures required for diamond formation.
|Obsidian nodule partially embedded in basalt|
|Upper surface of obsidian|
|End face of obsidian with larger air bubbles visible on the undersurface|