FMF - Friends of Minerals Forum, discussion and message board

[Robson Vieira]

Hi everyone, my name is Robson. I found this sample at a Ignimbrite dike, and i would like to know what it is. The features:
Luster: Dull, Earthy
Cleavage: Unseen
Specific gravity: 1.76
Hardness: 2,5 - 3,0
Streak: White
Solubility: No
Flamable: It is flamable, with a very dark smoke, then it turns to porous and very soft.
Fracture: Inexistent
Other: Its is sectil and the inner part has too fine 'cristals', like a powder. When brittled, it doesnt lead pieces or some else. It looks like wet in the inner part. I dont rule out man made stuff.

[vic rzonca]

"Flamable: It is flamable, with a very dark smoke, then it turns to porous and very soft."

Does the specimen have an odor prior to combustion? Rather odd. Was there an abundance of it or localized within the dyke?

[Robson Vieira]

Hi, thank you a lot. Yes, it had a odor like dust, or wet earth i don know exactly. At that place a found just one piece alone, i don know if there was more of that there. There i found also epidote, laser quartz, goethite, piryte, piryte recovered with goethite, jasper, and a beatifull blue mineral that i don know yet. Certainly, i will ask your help to it too. Have you any idea about yhe sample?

[vic rzonca]

The hardness and light greenish color reminds me of some odd marble I found in Marble, Colorado. It was not flammable, however, and I wondered if you detected a smell of hydrocarbons. Put a drop of HCl on it to see if it reacts.

[Dale Hallmark]

Kind of looks like a Variscite to me. It is puzzling.
Dale

[Robson Vieira]

Perfect! How could i forget such too simple test? I dont realize the needle to do the fizz test, but its done and the sample reacts, though quite slowly. Could it be a marble with a too fine powder formation? And why has it green color?

[Robson Vieira]

Hi Dale. Thats interesting your guess but the variscite is harder than this piece, because i tsted again the hardness and it was not be able to scratch a calcite crystal wich means H: ~2.5 and variscite is H: ~4.5. It reacts with HCL test, but slowlly...

[lluis]

Hi, Robson

If it is flammable, should be an organic compound, or an inorganic one soaked with an organic one.
If it has not a distinctive odour, could be just a high paraffin or something like that. Organic aromatic ones, like Karpatite, have a distinctive odour.

If it is easily flammable (just place a burning match and it burns), then could be just a sol of an organic solvent, that has included (or has been done) any inorganic compound, that is what rests after ignition.

For what you say, seems to me an hydrocarbon, maybe 18 C, gelified with silica gel (a looks like napalm...), that could be used as fire promoter when initializing a barbecue fire.
Colour, just a die brand....

All man made...
Slow fizzing could mean

-Some carbonates inside, probably from site
-Some holes that are filled with the water of reagent.

Both possible, but no idea of which one if I do not see the reaction.

I would just place the item in a safe place, and far from my mineral collection, to avoid an accident, and if you wish, with a tag that says "man made".

In case you wish, I can do an IR to know more, but I would just have a small sample.
Being flammable, would be a risk to mail it, and I am in Catalonia (an ocean between...), so...

Sorry to not be more precise, but I think man made barbecue initiator.... (not a mineral, then)

With best wishes

Lluís

[Robson Vieira]

Hi lluis, and thank you for the attention. First of all the sample is flamable, but it is not easily to do. Even a fire source as a match to close of it, delays a little bit to burn, and then, the sample again delay to delete the fire, wich is to modest. As i said early, i dont rule out to be a man made stuff, but ok i learned a lot with. Thanks.