<p>looks like a broken block of glass from a glass factory, called glass slag or chunk glass, you can get a whole range of hardness and color depending on what type of glass they were making. People often use it to make art.</p>
<p><a href="https://i.sstatic.net/nWYea.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/nWYea.jpg" alt="enter image description here" /></a></p>

CC BY-SA 3.0
2017-08-05T04:22:12.153Z
2017-08-05T04:22:12.153Z
2020-06-18T08:25:19.090Z
John
<p>Definitely looks like broken, human-made glass. The presence of bubbles pretty much clinches it.</p>

CC BY-SA 3.0
2017-08-06T01:05:35.657Z
2017-08-06T01:05:35.657Z
Dr. G
<p><img src="https://i.sstatic.net/5PmGL.jpg" alt="enter image description here"><img src="https://i.sstatic.net/pbZ1u.jpg" alt="enter image description here"> 
This Crystal has a couple gas bubbles and impurities in the very center of it it breaks only one way it is 4720 carats very beautiful very hard</p>

CC BY-SA 3.0
2017-08-04T17:37:39.213Z
I live in Oregon I traded a couple crystals for this rock because I thought it was really awesome never seen something like this before he said that it came from Brazil
Rick
CC BY-SA 3.0
2017-08-04T18:24:54.303Z
Please read our guide https://earthscience.meta.stackexchange.com/a/125/94 for rock identification questions. Inparticular the photographs are out of focus!
winwaed
CC BY-SA 3.0
2017-08-04T18:25:46.737Z
Hard to tell anything from the out of focus pictures, but the concoidal fracture and colour suggests man-made glass to me...
winwaed
<mineralogy>
What are these rocks
Rick
# What are these rocks

(Asked by: username_0 on 2017-08-04)

![enter image description here](https://i.sstatic.net/5PmGL.jpg)![enter image description here](https://i.sstatic.net/pbZ1u.jpg)
This Crystal has a couple gas bubbles and impurities in the very center of it it breaks only one way it is 4720 carats very beautiful very hard

**Tags:** mineralogy

> **Comments:**
> **username_0**: I live in Oregon I traded a couple crystals for this rock because I thought it was really awesome never seen something like this before he said that it came from Brazil  
> **username_1**: Please read our guide https://earthscience.meta.stackexchange.com/a/125/94 for rock identification questions. Inparticular the photographs are out of focus!  
> **username_1**: Hard to tell anything from the out of focus pictures, but the concoidal fracture and colour suggests man-made glass to me...  

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## 2 answers

### Answer by username_2 on 2017-08-05. Score: 4

looks like a broken block of glass from a glass factory, called glass slag or chunk glass, you can get a whole range of hardness and color depending on what type of glass they were making. People often use it to make art.

[![enter image description here](https://i.sstatic.net/nWYea.jpg)](https://i.sstatic.net/nWYea.jpg)


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### Answer by username_3 on 2017-08-06. Score: 0

Definitely looks like broken, human-made glass. The presence of bubbles pretty much clinches it.


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