Obsidian or Obsisian?

Obsidian is a type of naturally occurring glass, produced when felsic lava (from a volcano) cools rapidly and freezes without crystallizing first. Obsidian is named after one Obsidius, who discovered it in Ethiopia (according to the natural historian Pliny).

Obsisian is used as a synonym for obsidian (although I've only seen it used on sites selling jewelery that seems to contain obsidian elements), though you wont find obsisian in any dictionary that I know of. I assume it's origins can be found in the fact the "d" key and the "s" key are next to one another on the keyboard of typewriters and computers.

Obsidian is a rock and i've never heard of that other one.

Obsidian has to do with fossilized rocks.

Obsisian the dicitonary says nothing matches.

no there is no difference