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Identification Help (Native Bismuth)

Posted by Joe Mork  
Identification Help (Native Bismuth)
July 18, 2012 06:41PM
Hello! I was recently at a flea market in eastern Ohio as I live in the town of Sharon, PA which is close to the Ohio border. Anyways, I am an avid rockhound and collector, and have my BA in Geology. While at the flea market I purchased a glass canning jar full of Amber, Agate, and what I am almost positive as being Native Bismuth. I have ran every text imaginable here at home, but I would still like to be sure. Now I know the nearest mineral museum is that at Youngstown State University who may look at it, but I haven't asked yet. Does anyone know of anything else I can do?
avatar Re: Identification Help (Native Bismuth)
July 18, 2012 07:30PM
If you ran every test imaginable, that doesn't leave much to imagine. Did you run a specific gravity test? What was the result? Melting point?

Rock Currier
Crystals not pistols.
avatar Re: Identification Help (Native Bismuth)
July 18, 2012 07:33PM
de    
Please post a photo and/or tell us which tests you tried and what were the results.
Re: Identification Help (Native Bismuth)
July 19, 2012 11:09PM
Maybe not "every" test imaginable, but only those tests in which I could perform in my own home with the tools on hand. I apologize I am lacking pictures as I will attach them either later tonight or tomorrow.

Color: Metallic, almost a silver-white. Under the view of a microscope 2 samples contained very small vugs or openings. Within those openings the walls were an iridescent/metallic color to that color of the Hopper Crystals (rainbow). Also as with the picture, 1 sample contained a blue hue while looking at it, however through a microscope that blue hue is accompanied with other colors resembling those colors of the Hopper Crystals (a rainbow tarnish if you will) as well.

Streak: Silver-white

Hardness: Between a 2 and 2.5

Cleavage: Perfect in one direction

Fracture: Uneven and jagged

Specific Gravity: Between a 9.7 and 9.8

Crystal System: Hexagonal, some in the small vugs or openings are almost branching
Re: Identification Help (Native Bismuth)
July 20, 2012 12:49AM
ca    
Sure sounds like bismuth to me, however if you have small vugs with crystals in it, it is likely man-made bismuth. I don't know of any natural chunks of bismuth with vugs that contain crystals.
avatar Re: Identification Help (Native Bismuth)
July 20, 2012 12:52AM
de    
Bismuth is mostly more or less yellowish, but can also be light grey/silvery grey with no tad of yellow. Hardness and, more importantly, density also match well. When you say that cleavage is perfect in one direction, but fracture is unven and jagged, I assume that you have an aggregate with lamellar structure and that you have observed the parting of individual lamellae rather than the true cleavage (otherwise, an uneven and jagged surface would not make much sense when the cleavage is perfect). Lamellar aggregates are well known of native bismuth. What also comes to mind, as an alternative, is antimony, but this has a much lower density (ca. 6.8 g/cm3).

Thus, what you have appears to be bismuth. To be more conclusive, I need to see a picture, though.

EDIT:
A lamellar structure, if it is not particularly tight, also explains why you see "vugs" with crystalline structures in them. Thus, this observation does not necessarily mean that it is man-made.



Edited 1 time(s). Last edit at 07/20/2012 12:55AM by Peter Haas.
Re: Identification Help (Native Bismuth)
July 20, 2012 01:53AM
Peter,

3 pictures are coming in 3 different attachments which includes this one because of their size
Attachments:
open | download - 1.JPG (944.3 KB)
Re: Identification Help (Native Bismuth)
July 20, 2012 01:56AM
2nd picture
Attachments:
open | download - 2.JPG (896.4 KB)
Re: Identification Help (Native Bismuth)
July 20, 2012 02:02AM
3rd picture

If you need better I will try again in the morning. I wish I could show you the vugs, but my microscope isn't capable of capturing images.
Attachments:
open | download - 3.JPG (941.5 KB)
avatar Re: Identification Help (Native Bismuth)
July 20, 2012 10:53AM
ru    
This is 100% technical product and it is more similar to antimony then bismuth.
Re: Identification Help (Native Bismuth)
July 20, 2012 02:05PM
gr    
I agree it's certainly man-made/industrial product. The bright silvery color is also more consistent with native Antimony; Bismuth has a characteristic pinkish tint.

Lefteris.
Re: Identification Help (Native Bismuth)
July 20, 2012 04:09PM
at    
I also agree.
Re: Identification Help (Native Bismuth)
July 20, 2012 06:10PM
hu    
I don't disagree with all of you based on pictures, but what accounts for the density readings being off by about a half?
EMJ
avatar Re: Identification Help (Native Bismuth)
July 20, 2012 06:59PM
It almost looks like galena to me. I have seen weathered galena that has a patina similar to this. The crystals look more like isometric instead of hexagonal, there is one in particular that looks like it has a pyritohedron face and the others look more cuboctrahedron. I probably have those terms wrong. My crystallography is rusty. The main problem is the density. It is seems too high. Maybe the density should be recalculated.
Re: Identification Help (Native Bismuth)
July 20, 2012 07:13PM
I'm sorry I have to disagree about this being man-made and I have seen native Bismuth in this exact color and form. If indeed it was man-made that would not constitute the small vugs with rainbow colors which would tell what vugs in Bismuth to where crystals are formed are found. I have seen a lot of slag in every color and shape living near the Steel City of Pittsburgh and in the middle of coal country and I can tell you this is not it. At best I can take it to a local museum to be analyzed. I was very skeptical myself on the fact of what it could be. I ran another density test and came out with the same number.
Re: Identification Help (Native Bismuth)
July 20, 2012 08:08PM
hu    
The density being precisely that of pure elemental bismuth despite the material being admittedly somewhat vuggy suggests positive confirmation bias to me.
Re: Identification Help (Native Bismuth)
July 20, 2012 11:39PM
ca    
It does not look like bismuth to me. The cleavage is too weak and the colour is too silvery. However the cleavage is also too weak for antimony, maybe it is some sort of alloy. Send it out for EDS that should settle the matter.
Re: Identification Help (Native Bismuth)
July 21, 2012 01:20AM
I agree with Evan and Reiner. I wouldn't be surprised it it turns out to be an alloy and not a single element.
avatar Re: Identification Help (Native Bismuth)
July 22, 2012 05:42PM
ca    
'Technical Product" Pavel nailed it.
Re: Identification Help (Native Bismuth)
July 22, 2012 05:59PM
Thanks for the input and help. Gonna be taking it to YSU on the week of the 1st. If it is a man-made product I would like to know what
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