The photo is of material which was purchase in Moscow from a museum auction. It was set in a necklace with diamonds. There are diamond in the back side of the material
What I found strange about the metorite frgmaents is that they do not seem magnetic. I then put them close to a magnet and they are stongly magnetic to the magnet but not to each other. I can post some pictures of this. Tunguska event was in 1908 but material came from expidition of 1922. Wikipedia records indicate that no material was recoverd .Anyone with any idea of what material it is and how to date it.. as it may well be older than the earth.
So the questions are:
- are they real
- how old are they?
Fake meteorites can be made to look very convincing on the surface. It is much harder to fake the interior. It would be necessary to determine the density (as an indirect way of assessing the interior), and to do that first since it is non-destructive. However, that is likely to give only an indefinite answer. To be sure, it would be necessary to cut, polish and etch the specimen(s) - find out what it is really made of both chemically and mineralogically. If doing so exposed Widmanstätten texture, for instance, that would be a very good indicator that they really are meteorites.
Their behaviour with a magnet does not help determine their origin as meteoritic or not.
But as well as being real or not as meteorites, you would like to know if they are real in the sense of coming from the Tunguska event. I know no way of determining that.
You could also refer to the International Meteorite Collectors Association for an assessment of authenticity.
It would be necessary to use radioactive isotoptic dating techniques.
References: there are a lot, eg.:
- http://epswww.unm.edu/iom/ident/index.html (also a useful table of densities)
I wasn't sure, it being an airburst, that remains had been found, but this might well be of interest http://www.technologyreview.com/view/514511/first-tunguska-meteorite-fragments-discovered/ (seems to suggest that,though it could be from the expedition, & might also be a meteorite, it might well not be from the Tunguska explosion)
Thank for your information Mike
I cleaned up the two samples and they are silver, indicating a high nickle content
Checked the density just above 8
It passes all the test I can do at home.
Given the collection we have from the artist and our origianal skeptisim about the material I will look into it a bit more.
That's useful info.
It may be worthwhile bringing the specimens in to the NHM for folks there to inspect at close quarters.
I suggest you phone or email to make an appointment - at least to try to make sure somebody appropriate is there on the day.