Does blue obsidian exist?

Hell yes Emil, and thanks for that'n, beautiful
I'd say typical purple

It's not everyday I get to respond, but once in while an easy one...

I'm pretty sure blue obsidian exists, but the piece I had didn't look like the one in your photo.

The one I had was a light blue, like baby blue, and it was opaque, not translucent.

The piece I had looked more like this:

Ros that's also a beauty, but purple's more common

yours is called "tachylite". Its found with basalt deposits in small globs.
Real opbsidian will have a tanslucency variation when you hold it up to the light in one direction, then f you turn it 90 degrees It will be almost opaque.
This "birefringence" is a giveaway for obsidian v glass.
Just from looking at the photo, Id say EMILIANO's blue one is manufactured glass and not obsidian.
Theres a lot of scroungy folks out there trying to sell stuff as authentic.

Good'n, Man. How wish as a young rockhound I had broken more books

well, I just caught my own error. Im getting addled. The term for differeing colors when a crystal is viewed from different angles is called PLEOCHROISM , not birerefringence. Birefringence is the property of exhibiting "double refraction" (If you read a newspaper through a chunk of Iceland SPar, you see two lines of print for each one there).
Pleochroism is the ability for a crystal to absorb different wavelengths of the spectrum along different axes and thus exhibit different colors when viewed with transmitted light or under various wavelengths (like flourescent v incandescent)


Heres an example of a mineral with Strong pleochroic responses. Its clinozoisite (the variety is a gemstone called TAnzanite). You can see the different colors it exhibits in different wavelengths (not different axes in this case)

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Thanks Man, I'll try to remember that tho probably I won't. Still you're forgiven