Re: New Thread.



George wrote:

"Deirdre Sholto Douglas" <finch.enteract@xxxxxxx> wrote in message
news:448514B5.C5134223@xxxxxxxxxx

Additionally, there's no "limestone", there are
only various polymorphs and flavours of calcium
carbonate...

Umm, incorrect, since most limestone has only a percentage of it's
composition as calcium carbonate.

Which is why there is no "limestone" in my
world...I use pure chemicals not things which
can vary in composition...large errors bars
make me twitchy.

some of the old timers, however,
still refer to CaMg(CO3)2 as "dolomite"...

Gee, I guess that puts about 99% of all geologists in the catagory of "old
timers", eh?

Um. You said it, not me, but yes...the few I've
worked with seem to use very inexact terms
to describe things and it not always easy to
reproduce a geologist's work in a controlled
situation...I almost drove one to tears by de-
manding that the films he gave me be the
_same_ size, same composition and same
structure because "it worked fine without
that." Aye, well, it may have "worked" but
without that consistency it's damned hard to
analyse exactly _how_.

just as
they refer to Sodium Hydroxide as "caustic" and
copper sulphate as "blue vitriol". When I hear
"dolomite" it simply means they want a CaCO3
with a magnesium component.

No offense intended, but I'm glad you never worked in any labs where my
samples were analyzed. Fact: Dolomite is not simly "CaCO3 with a
magnesium component." It is a completely different mineral from calcite,
with a different atomic structure, and a different chemical, crystalline
and other physical properties, and has been recognized as such
internationally for over 150 years. Compare and contrast the following:

At the risk of insulting you...duh.

If you've a problem with the language used by
old timers, you'll have to take it up with them,
I call the stuff "Calcium Magnesium Carbonate",
dolomite is _their_ term, not mine, I've merely
had to learn what bottle they're trying to bor-
row when they use it.

You world obviously contain Big Things which can
be held in the hand, mine does not...your rock is
my e- acceptor/buffering agent...although I try
to avoid using carbonates and/or phosphates ex-
cept as needed for metabolism...a major pain,
they are, always precipitating when one doesn't
want them to and filtre sterilisation is a nuisance.
A right mess when uranyls enter the picture as
well, makes it hard to tell who's doing what.

Given that rather major difference in perspective,
it's not surprising we view the same things from
different angles.

Deirdre

Indeed. One of my favorite professors was an old chemist who hated
geologists (but liked me for some odd reason). I am correct, though.
Calcite and dolomite are separate and valid mineral species, and have been
recognized as such for a very long time. I suspect that you spend most of
your time, as you say, analyzing minute quantities of samples, are aren't
generally concerned with the intricacies of how and what various minerals
form rocks.

I use an x-ray beam fifty times smaller than
the diametre of a human hair...anything bigger
than a couple microns or so, is too big for my
purposes.

I only care if my little guys can take something
soluble like Cr6+ and mess with the electrons
to make it insoluble Cr3+...if that counts as
"forming rocks", then that's my sole interest
in the process. If it doesn't metabolise and do
something interestingly useful while doing so,
it's not going to hold my interest for long...my
job is to find biological remediators.

That's where I come in. At any rate, limestone is more
soluble than dolomite/dolostone, and so there are many more caves formed in
limestone than dolomite/dolostone.

And you are welcome to _all_ of them as I can't
abide caves...I have a rock climbing, spelunking
offspring and can only assume he's a throwback
to something on his father's side, because he
didn't get that trait from me.

Deirdre
.

Relevant Pages

  • Re: Quartz Origins (Uh-Oh, Another Geology Post)
    ... powdered dolomite not fizzing in an appropriate acid. ... other than it's being a different carbonate. ... I've also picked out limestone exposures in putative ... the term magnesian limestone to me is indistinguishable from secondary dolomite. ...
    (sci.geo.geology)
  • Re: Quartz Origins (Uh-Oh, Another Geology Post)
    ... The oxalic acid crystals I used may occasionally have been citric acid ... powdered dolomite not fizzing in an appropriate acid. ... other than it's being a different carbonate. ... I've also picked out limestone exposures in putative ...
    (sci.geo.geology)
  • Re: Quartz Origins (Uh-Oh, Another Geology Post)
    ... The oxalic acid crystals I used may occasionally have been citric acid ... powdered dolomite not fizzing in an appropriate acid. ... other than it's being a different carbonate. ... I've also picked out limestone exposures in putative ...
    (sci.geo.geology)
  • Re: New Thread.
    ... I thought Dolomite and Limestone to be the same. ... Are they not both mostly Calcium Carbonate? ... what distinguishes one rock from another. ...
    (soc.culture.scottish)
  • Re: Quartz Origins (Uh-Oh, Another Geology Post)
    ... The oxalic acid crystals I used may occasionally have been citric acid ... powdered dolomite not fizzing in an appropriate acid. ... I've also picked out limestone exposures in putative ... call a formation with various carbonates a 'Dolomite' or 'Limestone' ...
    (sci.geo.geology)
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