[meteorite-list] 'Mars' meteorite

From: Bill Southern <southerndesert_at_meteoritecentral.com>
Date: Tue May 9 22:14:37 2006
Message-ID: <20060510021435.91606.qmail_at_web31111.mail.mud.yahoo.com>

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 Tue 09 May 2006 10:14:35 PM PDT