Re: New Thread.



George wrote:

"Deirdre Sholto Douglas" <finch.enteract@xxxxxxx> wrote in message
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Madra Dubh wrote:

"George" <george@xxxxxxxxxxxxxxxxxxxxx> wrote in message
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http://www.youtube.com/watch?v=OU9N-ApYYJU

Now I've shown my ignorance.
I thought Dolomite and Limestone to be the same.
Are they not both mostly Calcium Carbonate?
What distinguishes one from the other>
(I was a spelunker of sorts in my youth, there being many caverns in
East
Tennessee)

Dolomite, as I recall, has a magnesium component
in the mix.

It's not the bulk components which are used to dis-
tinguish things, it's the minor ones. Hematite and
Lepidocrosite are both mostly iron, the difference
is how that iron is configured in the system.

Deirdre

That is not entirely correct. The major components of a rock are primarily
what distinguishes one rock from another.

It depends, I should think, on the definition of
"rock"...my world doesn't have rocks, it has
solid phase and soluble compounds and when
solid, they're never more than a few microns
thick, hence I distinguish things by chemical
conformation. Solid phrase iron compounds
frequently have the same bulk components, it's
the way those components are configured and
the minor additions which makes them differ
from one another.

Additionally, there's no "limestone", there are
only various polymorphs and flavours of calcium
carbonate...some of the old timers, however,
still refer to CaMg(CO3)2 as "dolomite"...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.

<shrug> It's in a different bottle on the same
shelf.

For instance, if there is more
calcite than dolomite in a sedimentary rock (carbonates being the primary
constituent), the rock is called limestone. If the predominant mineral is
dolomite, it is called dolomite, or more properly, dolostone.

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
.

Relevant Pages

  • 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)
  • Re: New Thread.
    ... Umm, incorrect, since most limestone has only a percentage of it's ... composition as calcium carbonate. ... "dolomite" it simply means they want a CaCO3 ... mine does not...your rock is ...
    (soc.culture.scottish)
  • 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: New Thread.
    ... I thought Dolomite and Limestone to be the same. ... Are they not both mostly Calcium Carbonate? ... The major components of a rock are primarily ...
    (soc.culture.scottish)
  • 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)