# What is this rock? **URL:** \ **Category:** Factual Questions\ **Created:** [February 3, 2011, 9:16am UTC](https://boards.straightdope.com/t/what-is-this-rock/570001 "2011-02-03T09:16:02Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Dog80](https://avatars.discourse-cdn.com/v4/letter/d/6bbea6/32.png) [@Dog80](https://boards.straightdope.com/u/Dog80)\ **Post date:** [February 3, 2011, 9:16am UTC](https://boards.straightdope.com/t/what-is-this-rock/570001/1 "2011-02-03T09:16:02Z")
[http://img96.imageshack.us/img96/8491/imag0256j.jpg](http://img96.imageshack.us/img96/8491/imag0256j.jpg) Looks like glass and is greenish. Is it natural or man-made? ---
**Author:** ![Maastricht](https://avatars.discourse-cdn.com/v4/letter/m/a88e57/32.png) [@Maastricht](https://boards.straightdope.com/u/Maastricht)\ **Post date:** [February 3, 2011, 10:20am UTC](https://boards.straightdope.com/t/what-is-this-rock/570001/2 "2011-02-03T10:20:53Z")
I’m no expert, but I would say man-made glass. [Obsidian](http://en.wikipedia.org/wiki/Obsidian) [is more opaque, has more inclusions, and is darker.](http://www.google.nl/images?q=obsidian&um=1&ie=UTF-8&source=univ&ei=bYFKTe3hE4mcOqyY6eUP&sa=X&oi=image_result_group&ct=title&resnum=4&ved=0CFgQsAQwAw&biw=1680&bih=959)Yours is blueish. It is not crystal, [quartz](http://www.google.nl/images?q=quartz&um=1&ie=UTF-8&source=og&sa=N&hl=nl&tab=wi&biw=1680&bih=959) or even smokey quartz; that would have a more crystal shaped stucture. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [February 3, 2011, 10:56am UTC](https://boards.straightdope.com/t/what-is-this-rock/570001/3 "2011-02-03T10:56:28Z")
Looks like glass to me. Any additional details on where you found it? ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [February 3, 2011, 11:04am UTC](https://boards.straightdope.com/t/what-is-this-rock/570001/4 "2011-02-03T11:04:13Z")
I looks like an aquarium decoration made from glass. It is glass for sure. ---
**Author:** ![Staggerlee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/staggerlee/32/3134_2.png) [@Staggerlee](https://boards.straightdope.com/u/Staggerlee)\ **Post date:** [February 3, 2011, 11:30am UTC](https://boards.straightdope.com/t/what-is-this-rock/570001/5 "2011-02-03T11:30:34Z")
Not sure, but try brandishing it in the direction of Superman if you see him. ---
**Author:** ![Snake\_Plissken](https://avatars.discourse-cdn.com/v4/letter/s/41988e/32.png) [@Snake\_Plissken](https://boards.straightdope.com/u/Snake_Plissken)\ **Post date:** [February 3, 2011, 11:32am UTC](https://boards.straightdope.com/t/what-is-this-rock/570001/6 "2011-02-03T11:32:59Z")
My sister has a chunk of glass that looks exactly like that. She got it from a guy that worked for the plant that made windows and windshields for Ford trucks. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [February 3, 2011, 1:16pm UTC](https://boards.straightdope.com/t/what-is-this-rock/570001/7 "2011-02-03T13:16:26Z")
Too clear to be [Trinitite](http://en.wikipedia.org/wiki/Trinitite) ---
**Author:** ![Sigene](https://avatars.discourse-cdn.com/v4/letter/s/df788c/32.png) [@Sigene](https://boards.straightdope.com/u/Sigene)\ **Post date:** [February 3, 2011, 1:21pm UTC](https://boards.straightdope.com/t/what-is-this-rock/570001/8 "2011-02-03T13:21:01Z")
I have a chunk of it at home that I use to knock out arrowheads common to find them in rock shops, ‘junk’ stores and pet stores