Identify if a Meteorite? Fusion Crust, Magnetic, Olivine

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SUMMARY

The discussion centers on the identification of a potential meteorite featuring fusion crust, magnetic properties, metal flakes, and orange olivine crystals. Participants assert that the rock likely does not qualify as a meteorite due to the absence of observable characteristics typical of meteorites, such as a true fusion crust and distinct olivine crystals. The consensus is that the rock resembles an Earth rock, possibly a greywacke or basalt, rather than a meteorite. For accurate identification, the inclusion of high-quality photographs and geological context is deemed essential.

PREREQUISITES
  • Understanding of meteorite characteristics, including fusion crust and olivine crystals.
  • Familiarity with Earth rock types, specifically greywacke and basalt.
  • Knowledge of magnetic properties in rocks and meteorites.
  • Basic photography skills for capturing geological samples effectively.
NEXT STEPS
  • Research the differences between meteorites and Earth rocks, focusing on fusion crust characteristics.
  • Learn about olivine crystal formation and identification in meteorites.
  • Explore the magnetic properties of various rock types, including volcanic basalts and meteorites.
  • Investigate local geological resources or universities for professional analysis of rock samples.
USEFUL FOR

This discussion is beneficial for amateur geologists, meteorite enthusiasts, and anyone interested in accurately identifying and classifying geological specimens.

  • #31
Het Patel -
Like the others, overall it does not strike one as meteoric origin.
Looks more like a dense basalt that's been river tumbled into the shape it now has.
Basalt can be magnetic since it's rich in iron.
It can also have olivine crystals which colors can vary.
A local university with a decent geology department should be able to thin section it and put it on a petrographic microscope which will definitively answer the question.
 
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  • #32
Baluncore said:
When the hot meteorite slows down and begins to cool in the lower atmosphere, the surface shrinks first, opening cooling cracks in the surface. Then the inside cools and shrinks which partly closes the surface cracks.
Actually, I will clarify that comment. I should have done so when I first read it.
Not all stone meteorites end up with a cracked fusion crust. Some are, most are not. See the examples I posted from my collection
near the start of the thread.

Contraction cracking is caused the strong cooling high in the atmosphere, 15 - 20 km or so. This can be as it passes through particularly
cool layers of the atmosphere. A fellow collector who does indepth meteorite studies commented that frost can form on the fusion crust
causing the cracks and in extreme cases a layer of ice can form, making those cracks even more pronounced.

Surprisingly, the inside of the meteoroid doesn't heat up overly much. Rock is a very good heat insulator.

My favourite cracked crust meteorite's is Ghadamis from NW Africa, Algeria, from memory.
This is a 1.45kg sample.

Brett Joseph 1.45kg Ghadamis2.jpg
 

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