GLASS ROCK found in woods (photos embedded) Need expert analysis.

reply to post by DenyFlatulence


I have some red is it worth anything?

reply to post by gariac

Oh, you have Geiger counter eyes?

Yes.
Can't you tell from my avatar?

A big chunk of salt?

Try tasting it?

reply to post by Stormdancer777

I have some red is it worth anything?

I'm assuming you mean red obsidian.
Yes. It's worth what someone is willing to pay for it.
I have some too. The reddish color is from iron impurities.

My Grandma had a huge chunk like that long ago, I loved it as a kid, do not know where it went. I think it was like an aquamarine quarts crystal. The value was to my Grandma and to us kids who enjoyed it as many things over the year including a door stop.

It would be fun for this to be of value for you, I hope so, only on page one of the thread so maybe an answer has come. Can you take it out of the bag for some pictures?

Hi there!

Dont got the time to check the whole thread for replies. But as a geologist I can say that it definately looks like a piece of quarts... It looks to me as there are the charachteristic conchoidal fractures that are typical for quartz.

When I saw the picture at first my immediate thought was ah a chunk of quartz... Reading through your post where you state that you found it near an abandoned mine makes it clear that its 99.99999% is a piece of quartz youve found



Quarts can look alot different in aspect of colors or transparency But either way you can always tell its identity by its conchoidal fractures and its hardness on the Mohs scale (7)

The value of it is ought to be very low. Mineral collectors always looks for the crystal to be in perfect crystal form (Euhedral) and this piece of rock you guys found, is most likely a broken piece of a bigger crystal... Resulting in the value to be very low.. :/

Here is a picture of a big quartz crystal with a good crystal form spiriferminerals.com...

An easy way to identify if its quarts is to check with aspect to Mohs Hardness scale. Or if you really dont believe my judgement to be fair. Break a little part of the stone and take it to closest university with a geology Section.

You can also Identify the rock by checking its chemical composistion. Like for instance with the use of a handheld XRF or a Secondary electron microscope. Even make a thinsection of a piece and look at it in a microscope... You can identiy the mineral easily with its characteristic Undulatory Extinction.

I think that will be enough!

reply to post by RockNrollRefUg


That is so beautiful. A good vibe from it.

reply to post by DenyFlatulence


I wasn't aware of that Bit rusty on my mineralogy these days! But no reason why obsidian can't have some colour differences, albeit, as you say, quite rare.

Anyway, IMO there is no way that the object found by the OP is any form of obsidian or any other rock or mineral I have ever heard of. Quart, for example, can be clear - but it looked nothing like quartz, which again fractures along straight lines.

reply to post by Explorarent


I would love to have that in my home!!! Wow, just gorgeous!!!

Ok, fun thread, informative too, just what I needed to read right now so thank you and best of luck on your great discovery and find.

I took a trip out to Arizona about 5 years ago, and there was this rock stand in a small town that was selling bulk glass like this for about a buck a pound. I bought some dark blue, light blue and clear samples that were about the size and shape of the one you were showing, but the edges seemed much more jagged. There was tons of this stuff, and the owner said it was broken chunks of raw glass manufactured by glass industries to be distributed to glass workers and blowers.

Inconceivable
Please take your neat find to a certified Gemologist. Any jewelry store in your area can recommend one to you. What if it turned out to be an incredibly rare huge semi-precious or precious stone? I would definitely have it checked out by a professional before just selling it to someone who says "Oh, it's nothing, just a piece of glass, but I'll take it off your hands for a hundred bucks" type thing, and they turn around and sell it for thousands or much more. I've been in the antiques business for over 35 years, so please take my advice. I've had things that looked like they should have been from a dollar store turn out to be worth hundreds, and in a few cases up to a couple of thousand dollars. Have it checked professionally, and do not let anyone scam it out of you or your friend for a pittance.

Although I disagree about the op's slag glass potentially not being slag glass.
This is great advice in general! I'm an amateur picker and it's not uncommon for me to purchase an item of interest for under $200 bucks and end up selling it for $1000 plus. I'll pay a lot more if I know for certain what something is worth but often times I have to gamble on an unknown curiosity. I often end up getting burned. It's all part of the game though.
Soo much fun!!

Do your research and take your item to an expert who will tell you what it might be worth. If they offer to buy it afterwards. Don't sell it to them. Ask them if it's a standing offer and get a second or third opinion. At the very least shop it around a little.
Watching Pawnstars makes me soo mad sometimes. lol.

reply to post by Stormdancer777


There is clear obsidian ....

www.google.com...:en-USfficial&biw=1516&bih=885&tbm=isch&imgil=1e KXx1xu6mH1KM%253A%253Bhttps%253A%252F%252Fencrypted-tbn3.gstatic.com%252Fimages%253Fq%253Dtbn%253AANd9GcTa7z64a1e2M4jKHvJF_AO8Ihq9UGj-w4iPu1Ae_8exvKFt c5p2sw%253B640%253B425%253BK09I6PG85gd1HM%253Bhttp%25253A%25252F%25252Fforums.opalauctions.com%25252Fviewtopic.php%25253Ff%2525253D17%25252526t%252525 3D3093&source=iu&usg=__Vf_Q1BlEgkpmK2a-Tn12UP4GDuU%3D&ei=10lIU9C5FePY2AXDkYDQDA&ved=0CCsQ9QEwAA#facrc=_&imgdii=_&imgrc=1eKXx1xu6mH1KM%253A%3BK09I6PG85 gd1HM%3Bhttp%253A%252F%252Fforums.opalauctions.com%252Fuploads%252F02-2012%252F84fc31af4a57b59f6f2289c2a043c053.jpg%3Bhttp%253A%252F%252Fforums.opalau ctions.com%252Fviewtopic.php%253Ff%253D17%2526t%253D3093%3B640%3B425

"The various colors of obsidian are a result of several factors. Clear varieties of obsidian contain very few opaque impurities or microscopic mineral crystals. Red or brown obsidian generally results from tiny crystals or inclusions of hematite or limonite (iron oxide). Abundant, microscopic crystals of minerals like magnetite, hornblende, pyroxene, plagioclase and biotite, combined with tiny fragments of rock, likely produce the jet-black varieties of obsidian. Microscopic crystals of various types of feldspars may yield the unique blue, green, purple or bronze colors associated with rainbow obsidian. The reflectance of rainbow obsidian is likely attributed to a preferred orientation of microscopic crystals of feldspar or mica oriented along flow layers."

reply to post by RockNrollRefUg


Maybe the geologist person can chime in on this? I have limited knowledge on the subject.

This is typically what green or blue obsidian looks like polished. Not claiming this to be a natural specimen though..

reply to post by Explorarent


How do you explain the large bubbles in it?
I'm curious and I love mysteries.
If it is in fact quartz that would be killer!!

[It appears to be glass of some old style make up. The air bubbles give it away.. per se.

reply to post by DenyFlatulence



The bubbles are what we like to term Fluid Inclusions. Almost no mineral is 100% pure. If you run a chemical analysis of any mineral you will always find lots of different elements in small quantities. Atoms of different elements are almost always contaminating the crystal gitter.

However fluid inclusions are fluid or gases trapped inside the mineral at the moment it crystalize. In geochemistry we can use it for geothermobarometers... In other words we can make use of the trapped gas or fluids to know at what pressure and temperature the mineral crystalized at.

The impurites can be very useful acting as geochemical fingerprints. For example... Certain minerals can act as indicator mineral... When prospecting for diamondiferous kimberlite pipes you can probe the Ca/Mg content in the Pyrope. If you get a value in a certain intervall the potential kimberlite pipe below youre feet have a much higher chance of being fertile etc.

reply to post by SixX18

Vitrification: Glass made by intense heat exposure.(defined form dictionary)

reply to post by SixX18


Perhaps this has been suggested already, I didn't read the entire thread, but I suggest examining it's physical properties if you want to find out exactly what it is.

The easiest property to measure is probably it's density. Use a precision scale to weigh it and measure it's volume by putting it into a container of water and note how much the water level rises. You can then calculate the density by dividing the mass by the volume.

You can then look up known densities for different materials and see if it matches. I don't think you'll be able to make a positive ID just from it's density but it might help rule out some possibilities. Note that the density might not even be meaningful since it might have more than one mineral or substance in it (as you said it has bubbles inside it, for example). But it does look pretty pure so it might be made of a homogeneous material.

Other than that, the only thing I can think of is measuring it's refractive index, which might be possible if you have a laser pointer. But this would probably be ridiculously hard unless the laser beam can be seen inside of the glass and you are able to find a reasonably flat region on it's surface to do the testing on.

It looks rather smoothed, you mentioned a Creek. I would venture it was in the creek or floodplain of it. Could it be slag glass from a smelting/furnace weathered done by the creek?