Molten lava has a temperature of around 1200 degrees celcius.
Once this lava has hardened how can I bring it back to the molten
state in an artists studio situation? We have considerable heating
devices in the form of kilns and furnaces.

Hello,

What an interesting question!! 

Re-melting lava depends on many factors like presence of water, grain
size and time. The type of rock is also important. If you were trying
to melt Hawaiian basalt lava, it would not melt, but it would glow
bright orange. If you were trying to melt granite or a mixed sediment
(not pure quartz or calcite, which occurs on some beaches), it would
almost certainly melt. The presence of water in the rock is important
to lower the melting temperature. Check out more details on this page.
http://www.soest.hawaii.edu/GG/ASK/melting.html

There is one more experiment done on a similar line. However, complete
details are not available. You can check for the experiment over here.
http://home.earthlink.net/~jimlux/lava.htm

Search term used:

How to melt lava

I hope this answers your question. Feel free to ask for clarification
and if I answered your question, then do rate it.

Regards
netcrazy

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Request for Answer Clarification by lavagirl-ga on 31 Jul 2002 06:47 PDT

Thankyou for your answer, although it was relevant all it told me is
that it is possible. That I already know. The question was HOW can I
bring lava back to its molten state.
Thanks for taking the time to answer my original question
Lavagirl

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Clarification of Answer by netcrazy-ga on 01 Aug 2002 08:37 PDT

Hello,

Even after searching extensively, there is not much of data available
for this type of experiment. But, I did find some related links, which
I thought, might be of some help to you.

A similar topic has been discussed over here in one of the Google
groups.
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=utf-8&threadm=3C9DEF9D.ADFE5EBC%40earthlink.net&rnum=7&prev=/groups%3Fq%3Dlava%2B%252Bmelt%2Bat%2Bhome%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3Dutf-8%26selm%3D3C9DEF9D.ADFE5EBC%2540earthlink.net%26rnum%3D7

Melting of lava is similar to melting of glass. Details about this are
given on this page.
http://www.rps.psu.edu/lab/

A Lava Experiment. This page is in Korean language. 
http://sarl.kaeri.re.kr/nanggak/LAVA.html

You can use ( http://babelfish.altavista.com/ ) site to translate the
above page.

I hope this answer will help. 

Thanks
netcrazy

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Clarification of Answer by netcrazy-ga on 05 Aug 2002 13:42 PDT

Hello again.
Thanks a lot for 5 stars. 

I mailed regarding the remelting of lava to USGS and Jim Flocks, a
geologist, replied me the following.

***********************************************************
I have never actually remelted magma, but it is done in the lab.  I 
do know that magma melt ranges from 1000 to 3000 degrees celsius, so 
it would take a high temperature furnace to reach the lower limit. 
The higher the silica content the easier the melt I would assume.

I searched our AAG database and could find no information on the 
methodology behind melting magma.  You can try some of the 
volcanology websites, such as http://volcano.und.nodak.edu/vw.html 
and http://vulcan.wr.usgs.gov to see if there is further information.

Good luck
Jim Flocks
Geologist
USGS Center for Coastal and Regional Marine Studies

***********************************************************
I hope this will help you more.
Thanks
netcrazy

Thanks
This was a difficult question and you have given me a great start.

If you take a rock and melt it, when it solidifies on cooling it will
probably not look like the rock you started with.    Potters, glass
makers and metal workers have been melting rocks for a few thousand
years, the desired outcome of their work is usually fairly refined and
homogenous. Where melting is the objective it is usually accomplished
by the addition of fluxes which lower the melting point and "soften"
the melt.  If your objective is to shape the "lava" in some way and
you are looking to produce a natural glass (some "lava" is very glass
like to begin with), then using fluxes to reduce melting point and
improve melt handling may be OK. The bubbles which are commonly
present in some lava and/or any crystalline minerals will probably not
survice melting.  My experience in melting rock comes from the assay
laboratory where samples of all types of rock may be fused with fluxes
as part of the assay (evaluation) for gold.

The type of the lava you will get will depend on both the melting and
the method cooling, as well as what you start with. You may find
http://volcano.und.nodak.edu/vwdocs/frequent_questions/group1_new.html
a good FAQ.

What do you want to achieve by melting solidified lava?

Do you want a cheap source of materials?

Do you want a finished product that resembles lava?

Do you want to make a souvenir of your local volcano?

Do you want to free a virgin sacrificed to the volcano god?

The melting of rock is a very complex process.  To see how complex, do
a Google search on "incongruent melting"  The page by Steven Dutch is
very good.

When rock melts, the liquid has a different composition than the
solid; this is called "incongruent melting."  (Of course, if you melt
all of the solid without loosing any of the liquid, the resulting
liquid has the same composition as the original solid.)  A consequence
of incongruent melting is that you can get a liquid that has unmelted
solids suspended in it.  You may reach a point where you have created
a lot of liquid, but can not get the temperature high enough to melt
the remaining solids.

Also, the process of solidification is just as complex as melting. 
The liquid solidifies in the reverse of the process by which it was
created.  The problem is that, with rocks, the chemical reactions that
occur during crystallization can be very slow to take place.  If your
lava cooled over a period of years, or millions of years, something
you make in the studio in a few hours, days, or weeks might not look
anything like the material you started with.  In fact, it is quite
likely that whatever lava you start out with, you are going to produce
glass.  If you have basaltic lava, the glass will be black.  If you
have granitic lava, the glass will probably be a nondescript gray.  In
either case, your studio "lava" is likely to have a lot of blemishes
caused by partial melting and incomplete crystalization reactions.

Let us know what your purpose is, and we may be able to give you a
clearer answer.