[meteorite-list] 'Mars' meteorite

From: Gary K. Foote <gary_at_meteoritecentral.com>
Date: Wed May 10 08:30:42 2006
Message-ID: <44619332.11668.22169C_at_localhost>

VERY very faint grey streaks. VERY faint.

ary

On 9 May 2006 at 19:14, Bill Southern wrote:

> A simple streak test will ID either..
>
> Magnetite - greasy black or grey streak
>
> Hematite - Reddish to rust brown streak
>
> On unglazed porcelain.
>
> Bill
>
> --- Elton Jones <jonee_at_epix.net> wrote:
>
> > Gary K. Foote wrote:
> >
> > > It looks more like a huge hematite node. Even its
> > crumbs are magnetic. Pieces from it are flakes,
> > rather than 'chunks'.
> > >
> > >
> > Hello Gary,
> >
> > I respect that you took the time to actually go see
> > this over-hyped
> > paperweight . This is clearly a rock of igneous
> > origin with minor
> > metamorphism possible. However the likely magnetic
> > component is
> > magnetite for the following reasons.
> >
> > While it is hard to do good ids from photos,
> > Probability-wise this is
> > from a pegmatite which could be local or glacially
> > transported in the
> > same vein(pun intended) as the deposits of Balmat
> > New York or St
> > Lawrence County or even Quebec Canada. The mass
> > looks like a classic
> > actinolite-tremolite-pyroxene group composition
> > along with about 15-20
> > other minerals. The three which are likely the
> > cause of the magnetic
> > attraction are Chromite(>2% chance) or Magnetite
> > (>90%chance) and
> > secondary hematite (>5%chance). If there is a talc
> > trend (aka
> > soapstone, greesy feel) or any iron sulfates (
> > brass-colored, metallic
> > flashes aka Pyrite Group) this indicates the mass
> > had some hydrothermal
> > alteration and hematite could be present. In a non
> > perfect world, I know
> > there is some hematite in the mass-the law of
> > probability says so but on
> > the order of less than .001%. The law of probability
> > also says the
> > magnetic attraction is due to magnetite in micro
> > crystals within the
> > mass. Hematite is usually associated with
> > sedimentary deposits but can
> > be found natively in metamorphic and igneous rocks.
> >
> > Actually the composition of this mass has a lot in
> > common with minerals
> > found in meteorites save for the hydrated silicates.
> > The holes are
> > likely from areas that were more hydrated and thus
> > softer than the
> > original pegmatite and therefore were gouged out
> > during rough ice or
> > stream transport--(if not actually human made).
> >
> > There is a long history of mining the magnetite
> > deposits of New England,
> > while else where in on the east coast the desposit
> > of iron are in the
> > from hematite and limonite(bog iron). Be it noted
> > that hematite is no
> > always magnetically attracted.
> >
> > In addition to magnetite, which can be truly
> > magnetic, there are
> > several other minerals that may be attracted to a
> > magnet(anistrophy of
> > magnetic susceptibility(AMS)).
> >
> <http://www.galleries.com/minerals/property/magnetis.htm>
> >
> > I am intrigued by the apparent attractiveness of the
> > plant stems on your
> > magnet--any theories?
> >
> > Elton
> >
> >
> >
> > ______________________________________________
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> >
>
>
>
> southerndesert_at_yahoo.com
> http://www.NuggetShooter.com
>
>
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Received on Wed 10 May 2006 07:16:02 AM PDT