An Article In Meteorite-Times Magazine
by Tom Phillips
Crystals in the Crust
NWA 2371 2950 gr. H4 classification by Ted Bunch (NAU).
My guess? I think it is some metal, or the like, in the meteorite that is crystallizing upon cooling. I should also start by saying, the only reason I am qualified to comment on this is, I am looking first hand at the feature and I am the only person doing this. Other than that fact, I am not qualified.
It appears the crystal structure is extending right out of ordinary meteorite grains. Grains that have many identical twins interior to the stone with no crystal growth. I have found absolutely no crystal structure away from the crust.
I think impurities in the silica such as metals could cause rapid crystal growth within the silica? What about pottery glazes? It is a layer of melted glass on the pottery. We have all seen beautiful Crystalline glaze. It is a mix of the right additives (often metals) in the silica that will rapidly crystallize upon cooling. I have seen it happen, the crystals grow like snow flakes. Couldn't that happen with melt?
My methods of high magnification reflected light examination reveal features that might not be detected in standard examination techniques.
This is the whole stone with slice 2950 gr.
Close up of slice.
Stereo microscope view of thick crust. Magnification 15 X.
Crystal structure show at a magnification of 700X.
Perhaps the most useful images, these shots show what looks to be crystal structure originating from grains within the meteorite matrix. These are also taken at 700X
Finally, some real close ups. These shots were taken at a magnification of 1600X.
Tom Phillips can be reached by email at:
The Tom Phillips Microscopic Meteorite Photography and Gallery