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Identity HelpVolcanic specimen

11th Jan 2019 11:28 UTCJunior Sto

Hello,

I wanted to get some opinions if I can put this specimen in the volcanic bomb category or some other type of volcanic material.

It is from a river valley in Buzau county in Romania.

It was collected 8 years ago and I washed away some lime deposits with anti-calc liquid. This treatment had some unwanted results because it rusted some flakes embeded in the crust and whitened what apears to be some kind of transparent glazing.

It’s magnetic so I assume it is a magnetite.

I wil post a little later the XRF results and a macro of a part of the ?ablation? crust.

11th Jan 2019 12:36 UTCJosé Zendrera 🌟 Manager

Looks like a volcanic bomb of basalt rock, which, among other minerals, always contains magnetite, hence the observed magnetism.

17th Jan 2019 19:30 UTCGregg Little 🌟

Another possibility is a chunk of pillow lava. IF it is basalt then this is more likely a flow feature rather than ejecta which is more commonly found with intermediate to acidic composition lava.

17th Jan 2019 19:48 UTCPaul Brandes 🌟 Manager

Probably not a volcanic bomb.

More than likely, this is some sort of relic of the Berca Mud Volcanoes although the colour is a bit off (maybe from the "treatment" you gave it?).

14th Mar 2019 21:42 UTCJunior Sto

Since I managed to gather more data on the subject I will share it here.

First test I did with a small slice was an XRF test.

14th Mar 2019 21:46 UTCJunior Sto

And today I finally got the X-ray powder diffraction test results.

14th Mar 2019 21:55 UTCJunior Sto

And also some very nice thin slices. In a few of them you can see at the top of the picture some nice olivine skeletal crystals.

I got an input from one of my friends that the Augite is really Hedenbergite.

Note the red mineral, I have troubles identifying it (maybe chromite?).

23rd Mar 2019 17:19 UTCJunior Sto

Since nobody seems interested in this topic I will post one last closeup picture of a small sample from the surface and will abandon this thread.

23rd Mar 2019 19:11 UTCDuncan Miller

Perhaps a smelter product, in other words, slag. The skeletal olivines and blocky magnetites are common in slags, and the pyroxene is due to the elevated calcium, perhaps from the kiln lining or an added flux.

23rd Mar 2019 19:39 UTCKrzysztof Andrzejewski

Junior Sto Wrote:

-------------------------------------------------------

> Note the red mineral, I have troubles identifying, it (maybe chromite?).

..................................................................................................................................

- in my opinion hematite with "limonite"-type mineral around

23rd Mar 2019 22:23 UTCPaul Brandes 🌟 Manager

Junior,

Please realise that if you don't get an instant response to a post, it doesn't mean folks have lost interest. Rather, many folks are traveling this time of the year and away from the site. Even I didn't know about your recent posts from March 14 because I was out of town on research. Sometimes a subtle "bump" is all it takes to get a thread going again.

Concerning your specimen; I thought at first maybe a relic from the nearby Berca Mud Volcanoes, but now looking at your analytical results I tend to agree that you may have a smelter product.

24th Mar 2019 20:57 UTCRalph S Bottrill 🌟 Manager

Yes probably slag.

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