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4.7 grams. unclassified
plagioklas writes:
This 4.7 gram stone has been sold as a NWA 4502 (CV3 Chondrite). While the other NWA 4502 specimens of the seller looked like CV3s, this one had an outstanding look. I gave it a try and risked buying it. After one month it arrived. This stone has most probably been collected on
the strewn field of NWA 4502, and no one has looked on it.
The stone looks really awesome and somehow unique. It consists of bright clasts (some of them are brecciated) in dark matrix clasts, which "swim" in a dark melt with a very similar dark color. The melt is just a little bit more transparent than the matrix of the large dark clasts. The stone consists of breccia in breccia in (melt-)breccia. The melt contains a few vesicles.
The stone contains several types of clasts. The most spectacular clasts are the feldspatic clasts, which show a snow white color and interesting patterns of different melt lines and structures.
The main clast is a 1.2 cm long monocrystalline plagioclase inclusion, which shows different degrees of shock. It is in some parts even broken in small cuboids, which are separated by thin transparent melt lines. Some thicker melt lines have cracks in their middle, which has been later filled with brown to black iron oxides.
Every of these features (including the cracks in the middle of melt lines) in the present size and look is a common impact feature of monocrystalline shocked plagioclases. That and the white color are the reasons why i assume that the inclusions are plagioclase.
Whatever this meteorite is, it is the most interesting impact breccia which i know of.
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Plagioklas
2/15/2013 7:01:29 PM |
The resolution of the picture is definitly not enough to show the remaining details. If you are interested, i can send detailled images. But im pretty shure, that this is an meteorite. Im very experienced in the determination of minerals and rocks and their genesis and have seen already thousands personally. But whatever. One day i will show it someone personally. But i will not let him cut hte stone,... its just too interesting and beautiful to be splitted into just another pile of small unattractive pieces and a thin section. |
Anne Black
2/15/2013 6:28:10 PM |
Thank you for the explication, but I am not convinced, this is not what I see on the picture. Maybe you should have it checked by an experienced lab. |
Plagioklas
2/15/2013 5:20:47 PM |
The remaining og my Post: This single photo shows not all details of the rock.
The probability of the combination of features and the way, how it came to me (sold as NWA 4502, while all other NWA 4502 of the seller are real CV3s) tells me, it is a meteorite. |
Plagioklas
2/15/2013 5:17:49 PM |
It is an impact melt with melt lines with included vesicles. The stone contains breccia in breccia in (melt)breccia. It has been found in an strewwn field of an meteorite. The other "CV3s" of the trader are real CV3s.
This rock contain multiple impact shock features, including melt lines, which run through some of the clasts, splitted some of em and contains mainly material which surrounds the lines (parts of lines through transparent/white parts and through main clasts are more transparent, parts of lines through dark parts are filled with darker material).
The melt lines are not typical for hydrothermal or pegmatic or in other non impact way filled cracks. They have mostly no clear border to the rim.
The clasts are white, but not quartz. They are softer than the matrix but most probably the same material as the matrix (no real borders in melt lines). Monocrystalline unshocked quarz in fine quarz would be harder or have at least same hardness. This single photo shows not all |
Anne Black
2/15/2013 4:05:12 PM |
I am sorry, but .... What makes you think that this a meteorite? Judging strictly from this picture, those white inclusions look like quartz, so I don't think it is a meteorite. |
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