Help identifying rock. Is this obsidian?

[MoraBob]

I found this at a garage sale. Correction. I found this in their garden and they were moving and i asked them to sell it to me. Paid $5 for it. Esee-4 for size reference.uploadfromtaptalk1360425382043.jpg

[sneakbox]

It sure looks like the Obsidian that I have

[clanmaki]

Looks like snowflake obsidian. The little white "snowflake" spots are little impurities that make flintknapping impossibe for this type of obsidian. But is great piece for display.

[BetulaLenta]

Maybe this is what you want to know for, or maybe not, but a good way to tell would be to smack it and see what the inside looks like. You can just flake off a small piece, not break the whole thing. Cortex (the outer, weathered portion of a rock) can be deceiving. Weathered obsidian and look very dull, but once you take a flake off, it's glassy interior is hard to mistake for something else. Obsidian cools so quickly when formed that it has no crystalline structure. The out side of your piece reminds me of glass slag with what looks like bubbles, but like I said, you can't always trust the outside.

[BetulaLenta]

Looks like snowflake obsidian. The little white "snowflake" spots are little impurities that make flintknapping impossibe for this type of obsidian. But is great piece for display.

Thanks for that insight. I was disregarding the little stuff that sometimes makes its way into obsidian in my response- just because it has some impurities in it doesn't mean it's not obsidian!

[Bones01]

Just a little safety hint.
If you decide to start flaking or chipping it out, wear those safety glasses without fail. It looks like the snowflake obsidian as mentioned but you won't know for sure until you start playing with it.

[NJWHN95]

I've gotten sparks off of obsidian before (don't know about the "snowflake" obsidian though) so you could try that and see if it works. It's not 100% foolproof but hey, if it looks like obsidian, feels like obsidian, and sparks like obsidian... it must be obsidian.