[meteorite-list] 'Mars' meteorite

[Gary K. Foote]

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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