Naked Science Forum

Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: Iwonda on 23/02/2020 04:56:46

Title: Is this coloured material a mineral?
Post by: Iwonda on 23/02/2020 04:56:46: This stone was found out in the middle of the desert, it was washed out of the side of a mountain by rain. When it was scanned I was told that it appears to be a mineral but there was nothing in the database that matched that composition. A close look at that colored material shows that it was boiling hot and outgassing when it was splattered on that quartz.
It has fused with the quartz and is about as hard as the quartz, takes a hammer and chisel to remove a piece of it.
Any ideals as to what it might be and if this is a mineral, at what tempt would such a mineral boil and why such high oxygen?
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Title: Re: Is this coloured material a mineral?
Post by: chris on 24/02/2020 22:20:47: Where (geographically) did you find this?
Title: Re: Is this coloured material a mineral?
Post by: Iwonda on 25/02/2020 03:23:34: Quote from: chris on 24/02/2020 22:20:47
Where (geographically) did you find this?
It was found embedded in a mountain side out beyond Lancaster, CA, in the desert area.
Title: Re: Is this coloured material a mineral?
Post by: Bass on 17/03/2020 20:14:19: Looks like desert varnish
Title: Re: Is this coloured material a mineral?
Post by: chris on 27/03/2020 18:39:45: Quote from: Bass on 17/03/2020 20:14:19
Looks like desert varnish
What's that?
Title: Re: Is this coloured material a mineral?
Post by: Bass on 27/03/2020 20:48:12: Desert varnish or desert patina is thin (micrometers thick) layer of iron and manganese oxides and clays that coat the surface of rocks on the surface in arid environments. Commonly red to brown to black.
Title: Re: Is this coloured material a mineral?
Post by: chris on 28/03/2020 08:54:27: Is that done at ambient temperature? I thought OP says it looks like the deposit was outgassing when laid down?
Title: Re: Is this coloured material a mineral?
Post by: Bass on 31/03/2020 16:54:53: Yes, at ambient temperature. I don't see any evidence for "boiling hot outgassing". It's common for desert varnish to coat just the exposed side of rocks.
(https://dazzlerplus.files.wordpress.com/2013/04/img_0799.jpg)
Title: Re: Is this coloured material a mineral?
Post by: Iwonda on 19/07/2020 05:58:27: This is the first I've ever heard of desert varnish, look very cool. However, I don't think it's the same as what's coating this stone. I took this stone and several others to a rock and mineral show and was told that it appears that these stones have been exposed to an environment where the tempt and pressure were extreme. I'm told that these black bubbles are signs of outgassing. [ Invalid Attachment ] [ Invalid Attachment ] [ Invalid Attachment ] [ Invalid Attachment ] [ Invalid Attachment ]
Title: Re: Is this coloured material a mineral?
Post by: evan_au on 19/07/2020 09:11:34: Quote from: Iwonda
these black bubbles are signs of outgassing
If they were spherical pits in the surface (as some of them are), that might indicate bubbles that were popping as the material hardened.

But I see that many in the more recent photos appear to be filled with black spheres, which would imply that the spherical pits are places where the black spheres fell out(?)

It may be an optical illusion; but the shadows with side lighting on image 5.jpg suggests it is a shiny sphere projecting above the surface, rather than shiny spherical depression.

Spherical balls of molten meteoric dust do land all over the Earth, all the time (some researchers found them in the gutters of residential houses). So it is possible that these spherules have been incorporated into desert varnish.

Possible meteoric origin: https://en.wikipedia.org/wiki/Micrometeorite
Other possible sources: https://en.wikipedia.org/wiki/Microspherulite
Title: Re: Is this coloured material a mineral?
Post by: Bored chemist on 19/07/2020 10:38:29: That many meteor leftovers in one place is, to say the least, improbable.
My guess is some igneous rock with materials separating into two phases as it cools would be a better explanation.
It would be interesting (Though very tiresome) to pick out some of the black spheres and analyse them separately
Title: Re: Is this coloured material a mineral?
Post by: Iwonda on 20/07/2020 22:18:45: The scientist that first noticed these things was somewhat blown away, said that he had never seen anything like it. He suggested that I search the web and see if anyone has ever come across anything like this. There are two rocks like this one and two smaller ones with what I am told may also be larger bubbles. They do sorta look like the photos in the micrometeorite link but I can't see how they would be anything like that, just too many in one area. All I can do is keep looking and asking. Thanks.