An Article In Meteorite-Times Magazine
by Tom Phillips
NWA 3151 Brachinite
The thin section is a loan from Greg Hupe and this description of NWA 3151 was taken from Greg's site where some of this material is for sale.
"NWA 3151 is the seventh member discovered to belong to this very exclusive and ultra rare group. The Total Known Weight is exactly 1500 grams in a single oriented stone with a translucent honey brown crust. It measured 115mm x 130mm x 85mm prior to cutting. Even with the addition of NWA 3151, by weight, Brachinites are about as rare as it gets. They are even scarcer than Angrites, Lunaites and SNCs.
The measured mineral ratios are right in there with the other six known Brachinites and oxygen isotope testing prove without a doubt that NWA 3151 belongs to this impossibly rare group. Some may ask, "What about NWA 595?" Re-examination and oxygen isotopic analysis of NWA 595 indicate that it may be an ungrouped ultramafic achondrite unrelated to the Brachinite parent body making NWA 3151 the first unquestionable Brachinite to be pulled from the Sahara desert. Brachina, the first Brachinite to be found was first mistaken for a Chassignite because of the mineralogy. "
For starters! How cool! Bernd Pauli has provided me with these excellent wide field cross polarized light micrographs which nicely show the unique structures found in this material. Well done Bernd!
This first set that I have taken has a field of view of 0.95 mm which is approximately 70X. Until I make some changes to my scope, this is about as low of magnification as I can go. (I need a different sub stage light condenser)
This material had some interesting opaque minerals which do not show up in transmitted light so here are two sets of images taken in combined transmitted and incident cross polarized light. The first 5 have a field of view of 0.62 mm (100X) and the next set 0.40 mm (160X)
Field of view 0.40 mm (160X)
This slide was so beautiful close up! This set is shown with a field of view of 0.25 mm (400X). At this magnification a whole new world of structures open up.
Finally I take it to a real close look. Field of view 0.16 mm (760X). This magnification may not be relevant to classification work but I hope you can appreciate the beauty. To me, it is all about the art.
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