Re: i have some questions

Hello again Bob!

I appreciate, the links and you taking your time to help.

I'll visit the sites after the post.

Black Hills? Was it Spodumene?

Thanx for the info. Yes I've learned that water under pressure and heat is
nasty stuff. Pretty strange also. It's really a fascinating field.

Take good care,
andy



"Robert Flory" <wyogeo@xxxxxxxxxxxxxxxxxxxx> wrote in message
news:ddo7k9$gg2$1@xxxxxxxxxxxxxxxxxxx
>
> "Jo Schaper" <joschapern4ospam@xxxxxxxxxxxxxxxxx> wrote in message
> news:11fkr0cskfcqo88@xxxxxxxxxxxxxxxxxxxxx
>> Spike wrote:
>>> Hello;
>>>
>>> It's andy your rockhound pal.
>>>
>>> I enjoy learning about this very cool science, i really want to know the
>>> answers to these questions.
>>>
>>> See i think it's a good fit, i need info and you have it. It will fill
>>> in gaps for me, you get to show the world how darn smart you are.
>>>
>>> Remember a stupid question is better than a stupid answer.
>>>
>>> How long does it take a crystal grow, say beryl in a pegmatite.
>>
>> As long as it takes for the pegmatite to cool. Unless the beryl (or other
>> crystal is a later inclusion, that is all the longer it has.
>>
>>> Is it true or actually possible the surface rocks like beryl were
>>> created 50,000 feet below the present surface, and have just weathered
>>> away.
>>
>> This is presumed to be the origin of diamonds, which then travel up
>> 'pipes' to accessibility. I don't know about 50,000 feet, but I know of
>> several igneous bodies which are believed to have been exhumed from
>> beneath several km of rock.
>>
>
> Andy, I'm not an expert in the field, but I think that many of the
> pegmatites (at least the ones I've seen) were formed at relatively shallow
> depths. I've seen 13" long crystals in the Black Hills of SD.
> Historically the origin of these minerals was thought depend on particular
> temperature and pressures. However more recent work has shown the
> importance of all sorts of other stuff like water & CO2 partial pressures
> and a whole raft of other things. Generally the greater the pressure,
> the lower the temperature needed and visa versa.
>
> http://www.trinityminerals.com/articles/beryl.htm
>
> As to age relative to the surrounding rock, some are younger ...
> http://www.geocities.com/oklahomamgs/London/Pegmatite2.html
>
> http://pegmatopia.ou.edu/ and may others
>
> Thanks for the question, I now have re-learned things I'd forgotten and a
> few new things too.
>
> ;-)
> Bob
> http://www.trinityminerals.com/articles/beryl.htm
>


.

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