darcyj76
starting to shine!
Member since February 2021
Posts: 45
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Post by darcyj76 on Feb 16, 2021 0:44:17 GMT -5
Hello! I hope this picture works-would you agree that this is a green obsidian? It is about 8 pounds, and a friend had it in his yard, from the former owner’s garden, and he had no idea what it is. What do I do with something this big? Chisel and tumble?
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Benathema
has rocks in the head
God chased me down and made sure I knew He was real June 20, 2022. I've been on a Divine Mission.
Member since November 2019
Posts: 703
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Post by Benathema on Feb 16, 2021 0:59:05 GMT -5
I'm not convinced... But I'm no obsidian expert either. I've found a few decent pieces here and there and the conchoidal fractures to produce sharp and thin edges is pretty evident. In having a hard time picking that out here.
Edit. Dunno.
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Post by Garage Rocker on Feb 16, 2021 1:10:03 GMT -5
Might be a piece of slag glass.?
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Post by rockjunquie on Feb 16, 2021 8:12:58 GMT -5
Going with glass.
We have a big conglomerate of shops here called the Pottery Factory in Williamsburg. They sell big chunks of slag glass. I have some somewhere around here, though mine is not very attractive.
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Post by Garage Rocker on Feb 16, 2021 8:21:34 GMT -5
Here are a few pieces I had at one time, for comparison.
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darcyj76
starting to shine!
Member since February 2021
Posts: 45
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Post by darcyj76 on Feb 16, 2021 8:35:29 GMT -5
Oh yeah, you guys are right-slag glass it is!
Thank you for your help!!
Darcy
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mjflinty
spending too much on rocks
Member since September 2011
Posts: 356
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Post by mjflinty on Feb 16, 2021 8:57:24 GMT -5
If you see air bubbles... it is probably man-made glass. If you are after Green Obsidian, look up Burns Green Obsidian it is pretty green.
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Post by rmf on Feb 16, 2021 17:36:08 GMT -5
over the years we traveled west over several routes. On one such trip I can't remember if it was I40 west, I30, I20 I am pretty sure not I10, but west of TN we stopped by a place and there was a lot of the green glass slag as you have and the guy would bring a pickup truck full to you for $500. I did not have the bucks or the market but it was interesting. He had access to an old glass factory refuse. so not obsidian but pretty. there was a factory in Chattanooga TN that made glass for Coke that is similar so you can find it here too from time to time. Either that or it grows in some flower beds.
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agatemaggot
Cave Dweller
Member since August 2006
Posts: 2,195
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Post by agatemaggot on Feb 16, 2021 18:19:48 GMT -5
If the Green glass is slabbed , it will probably appear as regular glass. I had some and slabbed it for flintknapping and the Green color disappeared as it got thinner !
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Post by Pat on Feb 16, 2021 18:44:17 GMT -5
Looks like slag glass. Nice piece! jamesp. What do you think? Slag glass or?
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Post by stephan on Feb 16, 2021 19:56:55 GMT -5
Here are a few pieces I had at one time, for comparison. That cobalt blue is lovely. My favorite color to find for sea glass.
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Post by Garage Rocker on Feb 16, 2021 20:17:08 GMT -5
Here are a few pieces I had at one time, for comparison. That cobalt blue is lovely. My favorite color to find for sea glass. I pulled out some of the tumbles that were birthed from these pieces earlier this evening, prompted by this thread. That glass makes some interesting tumbles. The blue was especially striking. What say you, jamesp , do you have any opinion on glass? If that is not the most loaded question in RTH history...you tell me what is.
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darcyj76
starting to shine!
Member since February 2021
Posts: 45
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Post by darcyj76 on Feb 17, 2021 0:35:40 GMT -5
That cobalt blue is lovely. My favorite color to find for sea glass. I pulled out some of the tumbles that were birthed from these pieces earlier this evening, prompted by this thread. That glass makes some interesting tumbles. The blue was especially striking. What say you, jamesp , do you have any opinion on glass? If that is not the most loaded question in RTH history...you tell me what is. Can you post the tumbles you did with these? I’d love to see them!
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Feb 17, 2021 3:46:14 GMT -5
Looks like soda lime slag(not the British definition) colored with iron or chromium Pat Garage RockerPlease be cautious breaking that chunk into smalls darcyj76. The fragments can cut you real easily. Heavy blows with a hammer against a heavy chunk of glass can send fragments at high speeds. Safer to saw it into say 1 inch thick slabs and then gently hammer pieces off the slabs by striking the sawn faces. Less fractures are created this way too.
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Post by Garage Rocker on Feb 17, 2021 7:11:54 GMT -5
I pulled out some of the tumbles that were birthed from these pieces earlier this evening, prompted by this thread. That glass makes some interesting tumbles. The blue was especially striking. What say you, jamesp , do you have any opinion on glass? If that is not the most loaded question in RTH history...you tell me what is. Can you post the tumbles you did with these? I’d love to see them! One thing I do have is photos. Here is one with the slag glass, along with some obsidian and other misc glass. If you want your mind blown with some tumbled glass pics though, head over to jamesp profile and take a look. You're welcome.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Feb 17, 2021 9:54:53 GMT -5
I must have been asked a 1000 times how to tumble glass Garage Rocker. And told them a 1000 times to buy a Lot-O tumbler to do a glass polish. Most of them were glass jewelry makers on a Facebook glass group. Tumble polishing much of their glass jewelry work would have behooved them tremendously. I don't think a single one of them bought a Lot-O and gave it a try. If memory serves you nailed a polish on the glass the very first attempt. They look like your standard super quality tumbles Randy, well done. ETA I think you liked the blue glass. Cobalt is the most common way to go rich blue. The glass blower knows cobalt well. If he takes a tiny amount of cobalt rich 'coloring' glass and tosses it in a 50 gallon vat of molten clear glass it almost instantly spreads thru the big vat and turns it rich blue. It takes very little cobalt glass to make blue glass and it has some kind of chain reaction when it hits the clear glass and spread thru it.
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Post by Garage Rocker on Feb 17, 2021 10:15:32 GMT -5
I must have been asked a 1000 times how to tumble glass Garage Rocker. And told them a 1000 times to buy a Lot-O tumbler to do a glass polish. Most of them were glass jewelry makers on a Facebook glass group. Tumble polishing much of their glass jewelry work would have behooved them tremendously. I don't think a single one of them bought a Lot-O and gave it a try. If memory serves you nailed a polish on the glass the very first attempt. They look like your standard super quality tumbles Randy, well done. ETA I think you liked the blue glass. Cobalt is the most common way to go rich blue. The glass blower knows cobalt well. If he takes a tiny amount of cobalt rich 'coloring' glass and tosses it in a 50 gallon vat of molten clear glass it almost instantly spreads thru the big vat and turns it rich blue. It takes very little cobalt glass to make blue glass and it has some kind of chain reaction when it hits the clear glass and spread thru it. Yup, the Lot-Omatic shine machine. Tumbled the glass much like my rocks. No sweat for that ingenious contraption. I'd definitely take more of that blue, everyone grabbed that up pretty quickly. Interesting to hear how they make those colors and patterns. Those pieces you sent me (which I have still yet to feature, but will) show true artistry.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Feb 17, 2021 10:30:29 GMT -5
The Lot-O has the magic sweet spot for doing glass. It has to do with well tuned vibration characteristics. By the same token it delivers high polish to Mohs 7's quickly.
A classic example not to always blame the abrasives or recipe but the type of vibe for not arriving at polish or taking a long time to get a polish. A well designed vibe both speeds up and improves quality of a polish even with poor slurry conditions or poor choices of abrasives are used in many cases. IMO vibes could be improved to perform even better if further R&D was done. Especially for softer stones.
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Fossilman
Cave Dweller
Member since January 2009
Posts: 20,681
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Post by Fossilman on Feb 17, 2021 13:53:10 GMT -5
Slag glass tumbles great and can be shaped into many types of art...
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