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Greetings.

Anyone care to take a crack at identifying this?

My wife and I found an unusual rock while meteorite hunting on a So Cal dry lake. She thinks it may be a meteorite, (Olivine Diogenite Achondrite) and I think it is probably one of the many types of rocks formed in the earth's crust. But we really don't have a clue, and remain stumped.

Any ideas?

Thanks!

Some notes:

1. Exterior Fusion Crust: Unknown. Has what appears to be a weathered rind and some desert varnish.

2. Metal Detector: Registers ‘OVERLOAD’ on White’s GMT.

3. Measures approx. 3.790” L, 3.165” W 2.54” H and 4.195” on the diagonal.

4. Weight exceeds max on electronic scale. Trigger scale average is approx. 996 grams.

5. Density & Specific Gravity: Not tested. (Feels very dense, like a cannonball.)

6. Magnet Test: Moderate attraction to magnet on all surfaces. (Magnet ‘jumps up’ 1”)

7. Streak Test: Leaves no streak (multiples attempts.)

8. Scratch Test: leaves light scratches on glass.

9. Nickel Test: Results were positive. (Dimethylglyoxime.) Swab was bright red.

10. Presence of metal flecks throughout interior. (Somewhat dull & ‘powdery’ in appearance.)

11. Appears to exhibit re-crystallized rim 6-7mm in depth around circumference of cut section.

12. Interior has visible weathering or shock cracks

13. Entire interior surface has what appears to be minute shock cracks visible w/ 10X loupe.

14. Matrix appears translucent, (Orthopyroxene and Olivine colored ) with globular silicates interlocked.

15. No vesicles are present.

16. Chondrules: Unknown, not apparent.

17. Interior contains a myriad of inclusions of various shapes/sizes. Unidentified. (Chromite or Magnetite?)

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Greetings.

Anyone care to take a crack at identifying this?

My wife and I found an unusual rock while meteorite hunting on a So Cal dry lake. She thinks it may be a meteorite, (Olivine Diogenite Achondrite) and I think it is probably one of the many types of rocks formed in the earth's crust. But we really don't have a clue, and remain stumped.

Any ideas?

Thanks!

Some notes:

1. Exterior Fusion Crust: Unknown. Has what appears to be a weathered rind and some desert varnish.

2. Metal Detector: Registers ‘OVERLOAD’ on White’s GMT.

3. Measures approx. 3.790” L, 3.165” W 2.54” H and 4.195” on the diagonal.

4. Weight exceeds max on electronic scale. Trigger scale average is approx. 996 grams.

5. Density & Specific Gravity: Not tested. (Feels very dense, like a cannonball.)

6. Magnet Test: Moderate attraction to magnet on all surfaces. (Magnet ‘jumps up’ 1”)

7. Streak Test: Leaves no streak (multiples attempts.)

8. Scratch Test: leaves light scratches on glass.

9. Nickel Test: Results were positive. (Dimethylglyoxime.) Swab was bright red.

10. Presence of metal flecks throughout interior. (Somewhat dull & ‘powdery’ in appearance.)

11. Appears to exhibit re-crystallized rim 6-7mm in depth around circumference of cut section.

12. Interior has visible weathering or shock cracks

13. Entire interior surface has what appears to be minute shock cracks visible w/ 10X loupe.

14. Matrix appears translucent, (Orthopyroxene and Olivine colored ) with globular silicates interlocked.

15. No vesicles are present.

16. Chondrules: Unknown, not apparent.

17. Interior contains a myriad of inclusions of various shapes/sizes. Unidentified. (Chromite or Magnetite?)

This reminds me of another find that a member of this forum posted here recently. My guess was pyroxene, same as this one.

http://en.wikipedia.org/wiki/Pyroxene

Regardless- it doesn't look like a meteorite for sure.

Those dimethylglyoxime nickel tests are worthless as far as I'm concerned. While they might indicate the presence of nickel, they don't tell you how much.

Steve

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Steve, thanks for the response.

I agree with you that it is probably one of the variations of an ultramafic rock.

The DMG nickel test has been an unreliable indicator for me as well.

I ended up sending a sample of this rock to a lab, and should have results in 2 weeks or so.

Best regards,

Daryl

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Here's some easy to spot nickle in the sun light for you.

Hi, Frank. Thanks for taking the time to respond with a picture. We have 7 or 8 dozen stoney chondrites from all over, so we have a pretty good selection to look at.

The shiny elemental iron nickel flecks are not what we are looking for in this rock.

The wishful thinking, fat chance is that this may be an Achondrite, an Olivine Diogenite. The lab will let me know in 2 weeks.

There may be elemental nickel/iron in the matrix, but the visible metal (which there is a lot of) does not look like the normal chondrite shiny Fe,Ni flecks. I do not have the abstract for NWA 5480 handy, but I think the metal present is more along magnesium or aluminum...and these flecks, as noted above, are powdery, aluminum looking.

Below is a pic of NWA 5480, an Olivine Diogenite (Achondrite), and a 10X and 30X pic of our suspect rock (which has been sanded to 1500 grit). Click on them to check out the metal in both to see what I mean.

Hope to meet you in person at Franconia one day!

Thanks,

Daryl

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