It is a rarity but some Obsidian has been found with small Gas Bubbles in it which when chipped or broken it can have cavities. the Natural Museum in San Francisco, California, has been known to have some Samples for Viewing and study.
No. Obsidian is brittle.
One type of obsidian is snowflake obsidian, which is black with white mineral inclusions that resemble snowflakes.
yes obsidian is a crystal.
Obsidian is, itself, a mineral.
Obsidian is a natural glass.
Obsidian is an igneous rock.
Other names for obsidian is Apache tears, volcanic glass, and Black obsidian.
Snowflake Obsidian
how is obsidian dependent on minerals
Obsidian is not magnetic.
If their business is in dealing with obsidian products, and they do not own any obsidian mines, then yes they will need to buy it. If however they do not need obsidian then they do not have to buy it.
The common name for obsidian rock is volcanic glass.