Normally whenever I get some obsidian I’ll check and make sure it’s transparent, so I’ll take my light from my phone and see if I’m able to see the light through it or not
I usually test this with tumbles but you can test it with raw obsidian as well, in my experience the corners are best to try to see the light through when it’s a rough stone :)
I checked it with fire and burning incense and it didn’t melt. I also tried to make an indent on it with a butter knife and that passed. Its real.
Normally whenever I get some obsidian I’ll check and make sure it’s transparent, so I’ll take my light from my phone and see if I’m able to see the light through it or not