Green Obsidian?

[earthdog]

This woman, on another forum is trying to tell me and others that she picked this light green Obsidian herself back in the 60's in some place called Nass Valley.
I have a hard time believing that this stuff is obsidian. It looks like slag glass to me. She has also said some other stuff in there that is wrong, like telling a woman what she found in her backyard in Indiana was Obsidian. She also said in another post that Obsidian was one of Indianas natural gemstones....

I think I might be the only rock geek here. I know it looks a bit like slag glass but that's not what it is, not with those varying colors in it. And although it's close in color it won't be aquamarine, tourmaline or apatatite because those crystals only grow with parallel striations to them and never have humps or curves on their broken surfaces, only straight edges. it will be either opalized limb-cast (the opalized center of a piece of petrified wood) or else it is obsidian (volcanic glass) which can be found in a variety of colors. In either case, that specimen you have there will be quite rare and very valuable to a rock-hound or stone collector. The way to determine if it is opal or obsidian - look at it with a magnifying glass and try to see if it has any tiny round air bubbles in it If it has bubbles in it then it is obsidian, and if the bubbles are shaped a bit like little torpedoes then it is obsidian glass from a meteor strike. If it has no bubbles then that means it is opal.

Here is what the woman found in Indiana, 2 feet down in her garden.
I say it's slag and I say she is crazy.



Here is what she says is green Obsidian that she picked herself.




Her obsidian with a piece of slag.


I posted a picture of some of my slag and she said this piece didn't have any varying colors

[cpdad]

thats slag....for sure....no doubt about it....have them scratch test it.....not always reliable....we got a peice that is killer hard....but if we cut it...im sure it will be softer in the middle....but in any case thats slag glass...kev.

[catmandewe]

I have a piece of green clear rock from the rock warehouse that I thought at first it was glass, but it still has matrix attached to it. I am not sure what it is, I will have to dig it out and take a picture of it and maybe you guys can tell what it is, sure is pretty though.

Tony

[cpdad]

mine is blue....but looks exactly the same ;D..kev.

[earthdog]

I asked her and anyone else to show me, anywhere where that light green stuff is documented anywhere. No takers. I looked all over the net and at that mindat.org and no place has any obsidian that looks like that.

[cpdad]

jim...dont let them give you a hard time ;D....thats slag glass for sure....i got a peice that cp has on his display desk....that amethyst wont scratch on the outside ;D.

but yet we know its slag glass....we could mess with folks minds with that ;D...just hard on the outside.

that green is slag glass...it would make some purty stuff though...kev.

[Deleted]

The only expert I know of in green obsidian is Bob Rush (Bobby1) on this board. I recently went to visit him and he showed me his awesome collection of this type stone. He made a cab recently (cab section) of his material he collected from Davis Creek California. Before I left he made sure I had several pounds of this material, its pretty cool stuff.

The photos you showed from the vendor does look like glass. However I am no expert and you never know what different types you will find.

[Deleted]

Here is a example of Davis Creek California material:

[cpdad]

cool ....maybe bob will show up and set us straight....i still beleive pics shown are glass...still say its nice chit....glass or not....i just like green stuff ;D...kev.

[cpdad]

thats a killer nice cab....friggin unreal ;D....still think earthdogs poster is showing slag glass.

i kinda know its slag glass....just cause ;D....im not 100 percent sure....but i did stay at a holiday inn last night ;D.

wheres bob when ya need him ;D...kev.

[bobby1]

I have never seen Obsidian with that level of transparency, though some may have areas with some transparency. The semi-transparent material always has some red or black associated with it. Obsidian originates from volcanos and age-wise is relatively recent perhaps a few hundred to 100,000 years or so. In geologic times it degrades rather quickly. I wasn't aware that Indiana had any recent volcanic activity.
Here is a cab of Glass buttes Obsidian with some semi-transparent areas.

The Obsidian that I gave Tony has color layers that show green but no transparency or even any translucency.
This rock started out as a 30 lb piece that my dad and I dug about 20 years ago. The exterior showed some green but I hadn't got around to doing anything with it. Last summer my 10 year old grandson was wondering what would happen if he "tapped" it with another rock.
Here it is post "tapping"

When I started picking up the pieces so no one would get cut on the sharp pieces I saw that it had some amazing color. Much more than was evident on the outside.



The exterior has the typical weathering of this material.

There is a Green Obsidian that is actually a dull olive drab color, but it too has no transparency and absolutely no translucency.
Bob

[earthdog]

The woman swears she picked the stuff herself out in the wild. She said it was a 20# chunk that she broke, back in the 60's.

[ladyt]

My mother in law used to live in Indiana. She collected the colored glass slag that was all over the place from the glass factories up there. Those pics look like some stuff she has in her garden. Bobby, I love that green obsidian! It is awesome!

T

[Tonyterner]

Bob that green obsidian is awesome. I've never seen it that color before.

[stefan]

Well there you go- she collected it in the 60"s!!! No telling what she was picking up! Sorry to say but that is Slag- Nice stuff but nothing more than slag glass (ok maybe Man Made Green Obsidian??)

[agatemaggot]

They just found a green obsidian Clovis point in the Yuccatan, hope I spelled that right, peninsula that dated back better than 13,000 years. It was almost compleatly clear and it would have posed no problem reading through it. That Indiana material seems to have a lot of bubbles in it !

[MrP]

Bob That green is fantastic!!!!!!!.......MrP

[agatemaggot]

I had a piece of green Obsidian on my watched items list, it was up for bidding by

rock-n-utah an E-Bay store.

[Deleted]

There's your answer edog......she did pick up her "green obsidian" in the wild. Except it was man made slag left over from the factories. Thats probably why she swears its natural....she really believes it is because she picked it up herself.

Shannon

[mirkaba]

Hi...This is not a good pic but it is the only green obsidian I have. From somewhere in the western US. Don't know what the little brown spherules are but its sort of cool.....Bob