I am in search of the minerals that have magnetic susceptibility and also minerals that show response to electrical conductivity... Will be so nice if someone can guide me in this regard as to search minerals one by one take time.
Thanking you in anticipation
Dear Mr. Saeed,
from the succeeding tripartite subdivsion you will see that apart from the ferrimagnetic minerals it makes not very much sense to list all diamagnetic minerals.
The majority of minerals which do not accommodate iron in their lattice are diamagnetic yielding a negative moderate susceptibility, e.g., calcite and quartz. By contrast, Fe-bearing paramagnetic minerals give a positive read-out. Siderite, ankerite and some Fe-bearing phyllosilicates pertain to these minerals. Only a fraction of these minerals are ferrimagnetic, the most well-known of which are magnetite [Fe3O4], maghemite [γ-Fe2O3], ferroxyhyte [δ-FeOOH] and pyrrhotite [Fe7S8] which can also appear in sedimentary rocks. Another group of Fe-bearing minerals also quite common to sedimentary rocks differ from the afore-mentioned oxidic Fe minerals by their antiferromagnetic order such as hematite [α-Fe2O3], ilmenite [FeTiO3] and goethite [α-FeOOH].
I have been involved as economic geologist and mineralogist in IP studies and according to my knowledge and experience, there are multifacted properties which impact on the electric field, e.g., grain size, grain moprhology, grain orientation, alignment together with matrix graphite, porosity, grain distribution (massiver vs. disseminated) etc............. I hardly can imagine that such a simple list of minerals exists. It would contradict any experience.
Judging from your other thread I suspect of using these data for placer-type deposits.
In this case I would suggest to pass through case histories described by exploration geophysicists who deal with this type of sedimentary deposits.
With kind regards
H.G.Dill
Harald G. Dill Thank you very much for such a comprehensive explanation.
Dear Mohazzam Saeed: the most complete database I've found in the web, which includes RXD, optical, magnetic, and other data is RRUFF. It permits to go to a specific mineral, and even choose same species from different localities. Simply put RRUFF in the google finder, and there you have it. Try it! Regards, Sebastián Grande.
Best I know, any sufficiently conductive material will show paramagnetic properties. Copper, gold and lead are obvious conductive non ferrous metallics which, when exposed to a fluctuating magnetic field from a pendulum supermagnet produce eddy currents. that palpably oppose the swing of the magnet. The enclosed image shows me playing with a supermagnet on a string in the lab. I wave it over the mineral very carefully so to not touch and can see twisting and actually feel the back emf from the induced electrical activity as small eddy currents. I was surprised that the core with digenite worked so well.
In the field hunted for covellite with a metal detector once. It worked in the lab but we didn't find anything the one time I had a chance. Sadly, I actually missed a big new gold placer deposit nearby because I was in the wrong area. That's what I get for only having two days in the field then.
Anyway, in the lab looking at core the underlying metal table interferes so I had to pick up the sample. I then take the same supermagnet on a string and dip it into the core box testing the dust for magnetite. There is none. The crumbly digenite-like blue black soft copper assaying material has no magnetite to cause the test magnet to wobble.
A gold detecting "pinpoint" tool would be a simple thing to try out on core. My experience is that it is really no better than your eyes at finding strange conductive material. A pinpointer would be simple to automate to leave a record of your core work before "corescan".
It is a cute demonstration of how a simple metal detector works. I too looked about for a database for paramagnetic properties. I didn't find much. This simple test was never shown in my mineralogy classes. Strange. It wasn't shown anywhere in physics either.
Anyway, I had to test my own collection of minerals. Interestingly pyrite showed no obvious paramagnetic properties to my simple pendulum test however it obviously does show up on IP and resistivity tests in the field.
I'm sure I'm not the first to goof about with a supermagnet on a string on core....but dang those staples.
The supermagnet on a pendulum string is a crude 'Oetvos' test from physics lab history. For mineralogists, a supermagnet bar suspended by a string from its middle would be very very sensitive if you waved mineral specimens near it.
There was a Hungarian mineralogist in Brazil who worked on magnetic susceptibility of minerals some 20 years ago. His name Dr Harely ....
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