My Archaeological Find: Calling all rock geeks!

I've got a degree in Geology (not that that matters too much...), and from what I can remember, very few, if any minerals or crystals that look like your specimen have conchoidal fractures. The exceptions are extremely fast cooling material, such as obsidian and glass.

It would help to have the specimen in hand. From the info you've given, I'd say it's slag from an old burn site (home, or trash). I've gotten identical specimens from old burn pits and old home sites. The second rock you showed seemed very black.

I wouldn't quit my day job! Finding a diamond would be nice... although I'd imagine you'd be more likely to find one attached to a golden band, than to an alluvial Ice Age diamond... unless you were actually searching for diamonds and knew where and what to look for.

Nice rock though! I'd put it up on the mantle, and add it to the other treasures that usually reside there.

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Learning is not compulsory... neither is survival. W. Edwards Deming

I found the box with the pale blue-green obsidian! I gotta just love my ex-MIL, she helped me pack my boxes of stones up and what a sweetie she is, the stones I was looking for were right on the very top, including my one and only specimen of slag that looks so much like the obsidian. It's almost as if she knew I would want to find those stones without having to unpack all the other boxes. She must be psychic.

Anyway, I've taken some pictures of both the obsidian and the slag for comparison and will post them tomorrow after I get them cropped. I lucked out big time with my amateur photography, I'm so pleased, I was actually able to capture the opalescent pearlescense in a couple of photos of the obsidian, I didn't think I'd be able to do that!

Thanks naturelover. I'll check in tomorrow to look. Have a good evening..

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I love my Harley like a fat kid loves cake..

Not an expert, but it looks exactly like the slag I haul from the Ford plant it Tulsa,Oklahoma, to a recycling plant in Texas. You can see some pretty big piles of this stuff on the west side of Sapulpa,OK, right off hwy 66 at a closed up recycling plant too. Could shure be something else though.

The depth the rock was found doesn't necessarily indicate how long it's been there. If the land was ever plowed, or even had a small garden or building in the area, the depth of that rock could be caused by people.

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Well, I did the best I could to crop the pictures to get the best detail possible. The point of my posting these pictures is not to show that my obsidian or slag looks like GoddessKristie's unidentified stone. It's to show that there's a difference in the appearances between obsidian and slag, and also to show evidence that there really IS such a thing as pale blue or green obsidian with a pearlescent sheen to it as well as some faint opalescense.

The slag was picked up at a gem and mineral show (it looks a bit like an iceberg and has a little onyx bear perched on top of it) and the obsidian is a piece I collected from near the lava beds in the Nass Valley in northern British Columbia. The Nass is a very remote, rugged volcanic area in the mountains, there is no industry of any kind (most of it is native reserve or very old logging territory) and is notable not only for it's lava beds but also for it's unusual specimens of jade and for huge amethyst geodes. (The amethyst is smokey amethyst mixed with reddish citrine and AMETRINE, of which I also have some specimens but I didn't take pictures of those since they're still packed away.)

These first 2 pictures are of the Nass obsidian (it is about the size of a man's hand held flat).

Lying flat:



Standing on edge:



Here is the slag, it's slightly smaller than the obsidian and a darker shade of blue. Note how shiny and full of bubbles it is compared to the obsidian.





Here are the slag and the obsidian beside each other for comparison, note how clear the obsidian is:





This is the obsidian cropped and resized to show as close an example as possible of the pearlescense that is evident wherever light reflects on it. This is not prismatic, it actually looks as though the stone was dusted with pearly powder on the outer conchoidal surfaces and inside the stone. Whatever that pearlescense is, it won't scratch off, and when I chipped pieces off the larger piece that this one came from, it is evident that it is throughout the whole stone:



Here is another example of the conchoidal fractures on the surface of the obsidian:



And trying to show the yellow opalescence inside the obsidian:



I have seen other clear, light obsidians that are a definite blue, or a definite green, but the Nass specimens are the only obsidians I've ever seen that is such a pale blue-green and has the pearlescent sheen and opalescense in it.

So who knows what other colors of obsidians there are out there that are still unknown and waiting to be discovered? Just like all other avid rock-hounds I'm always on the lookout for new, never-seen-before specimens of minerals that are popping up to the surface with more and more frequency in the past 20-30 years.

My opinion is the OP's piece is a hunk of a combination of clear and milk glass, probably a stack of broken pieces, that were thrown in with a bunch of trash to be incinerated or maybe all lumped together as a result of a house fire. I have seen stuff very similar.

What the geology prof from OSU told me when I took some stuff to him once was that it is very hard to tell man made obsidian from nature's obsidian. According to his research (and I know some of you will consider this hearsay) is that slag and obsidian are basically made from the same stuff and made in the same way. The only difference is the original material. Glass is made from sand (crushed rock) that is superheated. Obsidian is made from rock through volcanic action and is supercooled. Either way it is a very nice piece.

I'm no geologist or rock hound, but I've seen so much slag and obsidian at flint knapper gatherings, I say slag.

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Nevermore

This has been a very interesting thread and I can't wait for the conclusion. I like a good mystery (but not too long).

Nl, the piece you are calling Obsidian, looks so much like slag. I have been to Tucson for the rock shows and Quartzite, I have never seen a piece of Obsidian that light color before. With no disrespect at all, I have a hard time believing that is Obsidian.

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I love my Harley like a fat kid loves cake..

If it's glass slag formed in place, it's close to the right colour to have been formed from old white-glass jars (say the type cold-cream came in).

If it was formed in place, on a regularly-used burn pile, it could easily build up two feet or so of ash, charcoal, and half-burnt stuff that all later composted quickly. Heck, you could get that and the slag from one big bonfire. Might be interesting to know whether the soil looked consistent with that, given that it might have last been used fifty years ago.

Earthdog, no sign of disrespect taken, I'm fully aware it's hard to believe. I've never seen obsidian like that at the Tucson show either, or at any other gem and mineral show. But as I said in my previous post, the obsidian did not come from the Tucson show, it is the blue slag with the onyx polar bear on it that came from the Tucson show.

As I said previously, the obsidian is a piece I collected myself - it's from the Nass Valley and collected during my teen years when I lived up in the far north in the 60's. That piece of obsidian came from a much larger piece (approximately a 20 pound chunk) that was picked up and thrown down forcefully from a height of 15 feet onto other rocks so that it shattered into many smaller pieces. A big mistake well learned and I still have the scars from where I got sliced by pieces of flying obsidian. It didn't just break into pieces, it practically exploded and shards of it went flying every which way. Maybe some day, if you ever get the chance, you might head north yourself on a rock-hounding expedition and find similar treasures from northern BC and the Yukon.
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I'd love to make it up there to go rock hunting. my vacations are already taken up for this next summer. Gonna ride the Harley out west towards Montana and Wyoming to hunt for Montana Agates.
My point about Tucson was that just about every rock and mineral known to man has come through that show. I'm not saying that it doesn't exist, I'm saying that I don't know anyone that has ever seen any that light green, besides you.

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I love my Harley like a fat kid loves cake..

Ok, NL, I posted your pictures of what you are calling Obsidian on a rock site. These people know their rocks and there is even an Obsidian expert there also.
What you have there is not obsidian. There has never been any light colored Obsidian, ever. I even put in a Google search for Obsidian in Nass Valley and not much came up at all. Hey I even have a website for you to look at about fake rocks that people are trying to pass off as the real thing. I have the feeling you won't believe anyone, even if an Obsidian expert tells you that what you have is not Obsidian, so take it for what it's worth.
http://www.the-vug.com/vug/vugfakes.html#obsidian
Scrool down about half way and click on "fake obsidian"

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I love my Harley like a fat kid loves cake..

Wow what a lot of pretty rocks and some that aren't rocks..

Naturelover - have you had your greenish colored rock that you said was Obsedian ever examined by anyone with all the initials after their name? Did they give you a cert of authenticity or whatever they give that says what you have is the real thing?

(not even sure that is given) but if you do, it could be scanned and posted and that would settle this question - '''maybe'''.

I have learned alot over the years and one thing I've learned is just because no one has ever send/heard/had/owned something, does not mean it does not exist. It just means that until the point someone does "discover" something..it is just unknown.

So maybe naturelovers rock is real..she didn't buy it, she said she found it.
So maybe her rock is the real thing and just no one else has ever seen one before..if so,,yippee. If not..it is still a VERY pretty something.

The OPs rock/slag thing is also very pretty. I have no clue what it could be as I dont' "collect" rocks, I try to get rid of as many rocks as I can by giving them away and stacking them up to make walls, walkways, or use to stop washing on my farm.

But I sure do like pretty rocks..mine are just the common old greyish, greenish granite looking rocks and some even are boulders that stick way out of the ground and are useful sorts for sitting and thinking about things, finding moss on, and sitting on to get cooled off when it is hot. I do find some quartz now and then and have enough sandstone to backfill a huge lake with..lol - I think it is pretty but not very useful..too soft to be much good for anything to build with and too hard sometimes to drive post hole diggers through.

At any rate, I've learned a bit here and love the shiny, polished rocks..but prefer the not so polished ones that are more natural.

Seems like a great hobby to have..let's see..doesn't eat, require vets or doctors, shavings, feeding twice a day and can be easily and quickly carried around the world. I'd say that is a fairly low maintenance type hobby..much more so than horses are.

Thanks for posting all the pretty pictures and I hope you all come to a resolution regarding the OP's piece and the debate regarding NL's rock.

I would like to find something like silver or gold on my farm..but I keep finding old rusty horseshoes, railroad spikes (never has been a RR here that I know about), old, old nails, moonshine still parts, and parts to machines, equipment and such that I have no clue what they are..I now have a five gallon bucket of RR spikes that I have no clue what to do with but throw away. It's fun finding "junk" though, never know what it is, but can guess till doomsday and imagine what it could have been used for.

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naturelover, have you ever had your "obsidian" tested? I wouldn't think glass would explode if dropped, but something harder and more fragile would. Highly improbable but a slight possibility it could be diamond or something similar. Does it cut glass, or haven't you scratch tested it?

Funny how this topic seems to have gotten hijacked to be growing into a discussion about vulcanism and glass. Maybe we should keep it going as a place to post pictures and discussions of new mineral finds. The topic certainly has the right title for a thread like that.

Earthdog, thanks for the link, I already had the-vug link on my favorites list and I do know a great deal about faked stones. I teach about stones and minerals on a different forum. I don't know who you sent my pictures to but whoever they are I'm guessing it's someone who isn't familiar with the Northern Cordilleran Volcanic Province and the minerals there. If they (or you) want some rock-hounding excitement in your lives then I recommend an extended field trip to the area some fine summer. If you think you might be interested there's more information here on this link http://en.wikipedia.org/wiki/Norther...canic_Province and included in that link is information about the location where my obsidian came from, the Tseax River Cone - http://en.wikipedia.org/wiki/Tseax_River_Cone and about the massive destruction and death of 2,000 native people that occured in the Nass valley with that eruption about 250 years ago (I think it occured in 1760 but not sure of the exact date). The Nass valley was littered for several miles with lava encrusted boulders comprised of the same glassy material as my specimen. The flows there include basaltic flows and silica flows. If I recall correctly it is part of the Mt. Edziza Provincial Park which is over 1,000 square km. This following link has some information about the black obsidians from the area, but no mention is made of clear blue/green.
http://en.wikipedia.org/wiki/Mount_E...uptive_history

Danaus and Sidepasser - no, I've never taken the obsidian to any 'authority' as there's never been a need to do so. But perhaps that's a good idea so I can find out whether or not the pearly inclusion is liquified perlitic mineral (perlite) which apparently is a common occurrence with vulcanism and does create a pearly appearance. I know that perlite is used in the slag glass industry for just that purpose. Yes I've done scratch tests, and it does scratch glass, and I've examined it under my microscopes. It's certainly not industrial slag as there's no industry in that vast area, and I know it's not diamond - it's too soft for that and also I doubt that there are diamonds anywhere in the world that are that color and that are the size of boulders as big as a man. If it really was diamond then all I can say is I'm really glad that whole area is relatively inaccessible and now protected as part of one of the biggest Provincial parks in the province. I'd sure hate to see it's pristine beauty destroyed by the diamond rapists.

Well, this has all been an interesting discussion but I think it's kind of reached a dead end for the time being. I hope that if GK finds out for sure what her stone is she'll post here and let us know.
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NL, I posted them on a rock forum where many people have commented on them.
Oh it's not at a deadend. Now we like discussing your "green Obsidian"
I just wonder why if it is true "green Obsidian" why it isn't documented anywhere, not even the web link you gave. It would be such an oddity from the normal Obsidian everyone is accustom to, that you would think it would be documented some where.
I believe it's not Obsidian and thats why there is no documentation of it anywhere.
Otherwise someone would make mention of a light green, transparent obsidian.
Go figure.
Think what you want about what you have but everyone here that has knowledge of rocks and Obsidian and the rock forum where I posted the pictures of your "green Obsidian" knows what it is.

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I love my Harley like a fat kid loves cake..

Not diamond, that's disappointing. Oh well, like you said, the area would be ruined by specimen seekers or corporate rapists.

And as for the color and clarity of this specimen, it all has to do with the minerals that went into making it. I would love to go hiking in that area, even if you could no longer collect rocks there. We visited an area in Utah that was covered with opal. It was so beautiful, but had collecting been permitted the area would have been ugly and gross. To see hundred pound boulders of opal is such a spectacular sight!

Earthdog, just because it isn't documented doesn't mean it's not so. After all, zoologists are still discovering new primate species.

OP, sorry about the hijack.

http://www.mindat.org/mesg-55-48054.html

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I love my Harley like a fat kid loves cake..