Rock Identification

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Looks like Molybdenum, here's a few other specimens off the net that look very similar. Its should feel greasy and and smooth to touch.

1392436935_1711.jpeg


1392436998_moly_rock_specimens.jpg
 
Hare_Twigga said:

its either galena or antimony in the quartz don't think its antimony its too bright the cubes would have been pyrite and the stuff around it looks like its oxidized out of the dyke dose the rock feel gritty like rough sand on a beach ? if so its a weathered dyke
 
Village said:
I think what we are incurring here is the problem between the deciphering of photos's and the real item. Many rocks on visual can look identical or similar. In the field three quick easy tests to confirm an identity is to streak test, cleavage test and hardness test. Usually the outcome of these three tests will allow you to identify a rock to a 95% probability in the field, without any real further testing.

Like in the case of Chalcopyrite, on visual it will look brassy when first broken, and tarnish over time, the actual streak test colour when drawn across a white plate will be metallic greenish black. Completely opposite to it's visual.

Streak testing is easy and cheap, you can find a set of plates here

http://www.pilbarageology.com.au/products/Streak-Plate-Set.html

A lot of people carry a loupe as part of their kit, which is great, aids a on a percentage of rocks, or minerals by as siting the eye in identifying the crystal system of the specimen, but this really test no four in the sliding scale. Tests one to three should be completed first.

To complement all this a good field rock and mineral identification book is required, a good one, both in comprehensiveness and portability can be found here

http://www.abcmaps.com.au/Image Pages/rmpng.htm

Like I said doing it from photos is hard, and not being stubborn, until someone tests the original subject specimen, I'm not convinced based on the photos that it is chalcopyrite, but more then happy to be proven wrong, looks to grainy and loose in the photo.

Happy hunting

John

good advice also some simple chemistry tests go a long way too :Y:
 
Hare_Twigga said:
Hardness will distinguish - but striae on crystal faces indicate pyrite
 

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