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Re: Geo vs Astro chemistry was Asteroid, Comet, etc. question

Hi list
This is a follow up to the previous post.
I think another common misconception is that Taenite(Ni,Fe) and 
Kamacite(Fe,Ni) occur only in meteorites.  

The following are terrestrial localities for Taenite from;

(1)Anthony et al.  Handbook of Mineralogy Vol. 1 Elements Sulfides 
Sulfosalts, 1990
p510.

Distribution:  In the USA in Josephine and Jackson Counties, Oregon; and in 
California, near South Fork, Smith River, Del Norte Co.  In Canada on the 
Fraser River, Lillooet district, British Columbia. Taenite is found in all 
octahedrite meteorites which exhibit Widmannstatten structures as well as in 
some nickel-rich ataxites.

Here are the terrestrial locations for Kamacite from ref(1) p 256.

Distribution:  Terrestrial occurrences at Blaafjeld, near Ovifak, Disko 
Island, Greenland.  In Germany, from Buhul, near Weimar, Hesse.  Otherwise 
from meteorites.

There also 5 locations listed for Troilite(FeS),  
Again these minerals are very rare in nature but must be taken into 
consideration when testing for nickel in meteorites.

There are numerous terrestrial minerals many times more common than the ones 
found in meteorites.  They include but are not limited to Pyrrhotite(FeS), 
Pentlandite(Fe,Ni)9S8 main ore of nickel and Nickeline(NiAs).  These will all 
give a positive test for nickel and can have the appearance of nickel-iron 
flakes.  The difference is that nickel-iron is malleable and the nickel 
sulfides have a conchoidal fracture.  They are also heavy and can occur with 
other magnetic minerals.
So remember when testing stony-iron meteorites for the presence of nickel one 
must be careful not to assume because it shows a positive it is a meteorite.  
All the test shows you is that it contains nickel.  It's time to send it off 
to a qualified university lab to be tested more thoroughly.
I also commonly see reference to a mineral called Josephinite from Josephine 
Co., Oregon.  Norton in RFS 1998 p228 states that "Josephinite is an iron 
mineral alloyed with minute amounts of nickel."  There is no mineral named 
Josephinite.  It is probably a mixture of taenite and other nickel minerals 
(if I find out for sure I'll let you know).  The use of this term should be 
discoutinued.  It is similar to noting a Juancheng as Heze.
Mike Jensen
Jensen Meteorites

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