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Identity HelpPlease help id

31st Oct 2019 23:43 UTCArmando Villaescuza

I had several experts look at this rock and each gave me a different answer. I know that it looks to be a fragmental breccia but the clasts dont seem to be layered, their all over the place with no perfered direction. The most confusing feature is that there's a clear glazing on parts and a black felt looking thin crust on other parts. Please help id this rock thank you

1st Nov 2019 00:01 UTCPaul Brandes Manager

Looks like a piece of slag to me...

1st Nov 2019 01:58 UTCThomas Lühr Expert


1st Nov 2019 06:54 UTCA. Mathauser

Agree - it is slag.

4th Nov 2019 06:47 UTCArmando Villaescuza

Well I did get an xrd lab test done with the results showing its a breccia composed of Tridymite, Augite Aluminian, and Magnesioferrite. It's definitly not man-made slag. I also found flow-lines on a couple of those black spots which resembles fusion crust.

4th Nov 2019 06:49 UTCArmando Villaescuza

As to it's origin, I don't know

4th Nov 2019 07:56 UTCFrank K. Mazdab Manager

Those minerals don't preclude slag.  You just have a silica mineral (a high-T polymorph), a pyroxene (high Al content also indicates high T), and a spinel. Those can be common minerals in a slag, depending on the slag composition, and the combined high-T mineralogy further supports a slag. There are rare natural slags, for example, where a burning coal seam cooks and maybe even partially melts an adjacent rock unit, but artificial ones are way more common and more likely. And if your sample wasn't found adjacent to a burning coal seam or a thick basalt dike (which can also cook adjacent wall rocks), it's not likely a natural slag.

4th Nov 2019 06:52 UTCKeith Compton Manager

Armando Villaescuza  ✉️

Would be interesting to see the lab test results.
Are you also saying that you had the results before posting ?
And you have given no indication of where it was found.

4th Nov 2019 07:31 UTCKevin Hean

Tridymite is used in the manufacture of refractory materials, so it's quite possible this is a slag of one form or another

8th Nov 2019 17:22 UTCArmando Villaescuza

I was under the impression that flowlines were features of meteorite fusion crust. Can slag have such features?

8th Nov 2019 17:49 UTCThomas Lühr Expert

The bubbles in that glassy mass are indicative for slag !

8th Nov 2019 21:10 UTCArmando Villaescuza

The conclusion of the xrd was breccia. So I must ask if slag is a breccia? 

9th Nov 2019 12:07 UTCThomas Lühr Expert

The conclusion of the xrd was breccia.
This statement is nonsense! This is like you would say 'the conclusion of wighing is that the color is blue'
A xrd can tell you what CRYSTALstructure you have. Thus, it is senseless to apply a xrd to amorphous (non-crystalline) stuff, like glass/slag is.
It would be interesting if you would post the xrd plot here. 

9th Nov 2019 03:47 UTCKeith Compton Manager

To me it doesn't appear meteoritic. Nor breccia.
You haven't indicated where it was found. 

Still looks like slag though.

9th Nov 2019 05:27 UTCPaul Brandes Manager

XRD will not tell you if you have a breccia.
Six different experts have said it's slag, I'd say that's pretty conclusive as to what you have......

9th Nov 2019 12:57 UTCPaul De Bondt Manager

Slag for sure.
As this is from a furnace, sometimes unmolted angular rock from the ore is included in it, what seems to be a natural breccia.
But it's not, sorry.

9th Nov 2019 13:45 UTCUwe Kolitsch Manager

Can slag have such features?

15th Nov 2019 19:19 UTCArmando Villaescuza

Well I maybe new here but I wasn't born yesterday. I know what slag is and looks like but since you "experts" all agree by this picture that in FACT it is slag, I'm unsure I should post my xrd results. Besides They maybe taken as fake.

15th Nov 2019 21:07 UTCThomas Lühr Expert

Please read

Especially Frank Mazdab's post ;)

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