# How do I get Molten Granite? **URL:** \ **Category:** Factual Questions\ **Created:** [June 21, 2007, 11:37pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927 "2007-06-21T23:37:46Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Hypno-Toad](https://avatars.discourse-cdn.com/v4/letter/h/b2d939/32.png) [@Hypno-Toad](https://boards.straightdope.com/u/Hypno-Toad)\ **Post date:** [June 22, 2007, 3:03pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/21 "2007-06-22T15:03:43Z")
[QUOTE=Sunspace] What would you melt it in? [/QUOTE] A melter. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [June 22, 2007, 3:11pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/22 "2007-06-22T15:11:09Z")
> [@](#): > > What would you melt it in? Look at my post #15 ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [June 22, 2007, 3:13pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/23 "2007-06-22T15:13:39Z")
If you’re asking about what container you can melt it in, you can use, for instance, graphite crucibles, or perhaps alumina. I’m not sure o their mps, but they’re pretty high. I’ve seen pictures of the things they use for melting glass after long usage, by the way – the firebrick the structures are built of are severely eroded. Molten glass, besides being monstrously hot, is also corrosive. ---
**Author:** ![Cervaise](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cervaise/32/16693_2.png) [@Cervaise](https://boards.straightdope.com/u/Cervaise)\ **Post date:** [June 22, 2007, 3:45pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/24 "2007-06-22T15:45:43Z")
[QUOTE=Harmonious Discord] I was trying to point out that you wouldn’t get granite when it cooled. [/QUOTE] That’s right. Just because you have molten rock, that doesn’t mean you can take it for granite. ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [June 22, 2007, 3:53pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/25 "2007-06-22T15:53:15Z")
[QUOTE=Cervaise] That’s right. Just because you have molten rock, that doesn’t mean you can take it for granite. [/QUOTE] Gneiss one! ---
**Author:** ![Polycarp](https://avatars.discourse-cdn.com/v4/letter/p/82dd89/32.png) [@Polycarp](https://boards.straightdope.com/u/Polycarp)\ **Post date:** [June 22, 2007, 4:57pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/26 "2007-06-22T16:57:19Z")
[QUOTE=Telemark] Gneiss one! [/QUOTE] What, do you keep your radio tuned to clastic rock stations? 😛 ---
**Author:** ![Hypno-Toad](https://avatars.discourse-cdn.com/v4/letter/h/b2d939/32.png) [@Hypno-Toad](https://boards.straightdope.com/u/Hypno-Toad)\ **Post date:** [June 22, 2007, 5:29pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/27 "2007-06-22T17:29:16Z")
God, the Schist you guys listen too… ---
**Author:** ![Phlosphr](https://avatars.discourse-cdn.com/v4/letter/p/c68b51/32.png) [@Phlosphr](https://boards.straightdope.com/u/Phlosphr)\ **Post date:** [June 22, 2007, 5:36pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/28 "2007-06-22T17:36:43Z")
If I wasn’t so sedimentary right now I’d be posting alot more, but I’m tired. :rolleyes: ---
**Author:** ![The\_Controvert](https://avatars.discourse-cdn.com/v4/letter/t/dec6dc/32.png) [@The\_Controvert](https://boards.straightdope.com/u/The_Controvert)\ **Post date:** [June 22, 2007, 5:52pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/29 "2007-06-22T17:52:05Z")
[QUOTE=Phlosphr] Thank you both. I learned a thing or two today 🙂 [/QUOTE] Consider your igneous fought! ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [June 22, 2007, 6:00pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/30 "2007-06-22T18:00:27Z")
Cast basalt is commonly availabe for tiles, countertops and other uses. Re what you can use for a high temperature mold, just what is the most heat resistant solid that won’t react with air? I would presume some metallic oxide like maybe beryllium oxide or alumina, but who’s the refractory champ? What is firebrick usually made out of? ---
**Author:** ![mnbvcxz](https://avatars.discourse-cdn.com/v4/letter/m/2bfe46/32.png) [@mnbvcxz](https://boards.straightdope.com/u/mnbvcxz)\ **Post date:** [July 16, 2017, 11:45pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/31 "2017-07-16T23:45:24Z")
Granite melts from around 2219 degrees F to 2300 degrees F. ---
**Author:** ![Bill\_Door](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@Bill\_Door](https://boards.straightdope.com/u/Bill_Door)\ **Post date:** [July 16, 2017, 11:50pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/32 "2017-07-16T23:50:02Z")
I’ve used zirconium crucibles for temperatures up to 1800 C. That should work for granite. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [July 17, 2017, 2:06am UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/33 "2017-07-17T02:06:38Z")
Compared to the age of the OP’s granite samples, the OP’s thread is nearly brand new. Nearly. Shame to see so many deceased dopers in one place. We miss ya. ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [July 17, 2017, 12:41pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/34 "2017-07-17T12:41:24Z")
> [@LSLGuy](#): > > Shame to see so many deceased dopers in one place. We miss ya. Is there something about geology that kills its practitioners off prematurely? I’m thinking like early chemists. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [July 17, 2017, 1:30pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/35 "2017-07-17T13:30:54Z")
> [@DesertDog](#): > > Is there something about geology that kills its practitioners off prematurely? I’m thinking like early chemists. Some vulcanologists had a run of bad luck a few years ago. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [July 17, 2017, 1:36pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/36 "2017-07-17T13:36:23Z")
(Okay, [24](http://articles.latimes.com/1993-01-25/news/mn-1676_1_galeras-volcano)is really stretching “a few.” Time and scientist bits really flies…) ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [July 17, 2017, 2:49pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/37 "2017-07-17T14:49:50Z")
> [@DesertDog](#): > > Is there something about geology that kills its practitioners off prematurely? I’m thinking like early chemists. I suppose it depends on how much time they spend looking up at cliffs saying “I wonder how unstable that stuff is?” 😃 ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 17, 2017, 3:21pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/38 "2017-07-17T15:21:06Z")
Depending on how you’re heating it, you can melt any given substance in a container made out of the same substance. Heat it from the top, like with a blowtorch or a powerful laser, and make a little molten puddle in the top surface. Now, molding it, that might be more difficult: You could use a chilled mold made of the same substance, but then you’d have a hard time separating the mold from the casting, and if you have some technique for shaping the substance into the mold, why not use that same technique for shaping the final product directly? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [July 17, 2017, 3:59pm UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/39 "2017-07-17T15:59:45Z")
> [@Polycarp](#): > > For semi-obvious reasons (a melting point varies greatly with differences in pressure), the Wiki article doesn’t give a specific melting point, but suggests that granites normally form around the “eutectic temperature” – the temperature at which different constituents of a magma mixture begin separately settling out as solids. This is a characteristic of granite. I don’t know the right terminology but it’s some kind of aggregate of minerals that is usually apparent to the naked eye. IIRC it’s also somewhat less dense than most other rock and large bodies of granite tend to float upward toward the surface. There are a lot of different types of granite though so I assume the term ‘granite’ itself doesn’t refer to any specific composition of materials, just the physical structure of the rock and the way it forms. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [July 18, 2017, 7:09am UTC](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927/40 "2017-07-18T07:09:51Z")
> [@DesertDog](#): > > Is there something about geology that kills its practitioners off prematurely? I’m thinking like early chemists. Besides the volcanoes mentioned? IME, malaria is the biggest killer of field geologists, followed by ice/exposure and animals ([bears](http://www.dailymail.co.uk/news/article-1038259/Man-eating-bears-kill-scientists-lay-siege-survivors-trapped-remote-forest-base.html), for one. If you’re really unlucky, [seals](http://www.independent.co.uk/news/science/leopard-seal-attacks-and-kills-british-scientist-snorkelling-off-antarctic-coast-97459.html)). Volcanoes are a distant fourth. > [@TriPolar](#): > > I don’t know the right terminology but it’s some kind of aggregate of minerals that is usually apparent to the naked eye. The term you want is “[phaneritic texture](https://en.wikipedia.org/wiki/Phanerite)” > [@](#): > > There are a lot of different types of granite though so I assume the term ‘granite’ itself doesn’t refer to any specific composition of materials, just the physical structure of the rock and the way it forms. No, it refers to both the composition (silica-rich, or “felsic”), and the way it forms (plutonic - emplaced in the earth - not volcanic - extruded). The emplacement usually dictates coarseness of the texture. Granite specifically is igneous rock with between 20% and 60% SiO[sub]2[[/sub] (quartz) with 35%+ alkali feldspar vs plagioclase. Similar felsic rocks of different compositions but similar texture are just “granitic”. Extruded, usually finer-grained rocks of “granitic” composition are called [rhyolite](https://en.wikipedia.org/wiki/Rhyolite). Granite, _sensu strictu_, is only one zone of a continuum of rock compositions. Behold! [The wonder](https://en.wikipedia.org/wiki/QAPF_diagram#/media/File:Qapf_diagram_plutonic_05.svg) that is the [QAPF diagram](https://en.wikipedia.org/wiki/QAPF_diagram). Bane of first year geology students worldwide. [Previous page](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927.md?page=1) [Next page](https://boards.straightdope.com/t/how-do-i-get-molten-granite/408927.md?page=3)