southforkmining
spending too much on rocks
Member since October 2006
Posts: 275
|
Post by southforkmining on Apr 3, 2009 22:38:38 GMT -5
|
|
docharber
has rocks in the head
Member since October 2008
Posts: 716
|
Post by docharber on Apr 4, 2009 0:41:41 GMT -5
The irridescence makes me think goethite, akin to hematite and magnetite. Check out the Graves Mountain web site for some pics.
Mark H.
|
|
|
|
Post by LCARS on Apr 4, 2009 1:50:44 GMT -5
I think the green color would indicate chromium, not too many ferromagnetic metals to choose from there...  |
|
Sabre52
Cave Dweller 
Me and my gal, Rosie
Member since August 2005
Posts: 20,492
|
Post by Sabre52 on Apr 4, 2009 9:16:42 GMT -5
I'd say jade with magnetite myself. That combination is common at the Porterville, CA Jade mine sites and many of the slabs I've cut from those sites will also attract a magnet. The green would probably be a result of iron content but chromium is often present too.....Mel
|
|
southforkmining
spending too much on rocks
Member since October 2006
Posts: 275
|
Post by southforkmining on Apr 4, 2009 10:08:01 GMT -5
Hi guys..thanks for the thoughts and ideas...does anyone have a picture of the porterville jade..I have never seen any...and pics of rough or polished pieces would be very helpful.......thanks guys...Rich
|
|
MikeS
fully equipped rock polisher
Member since January 2009
Posts: 1,081
|
Post by MikeS on Apr 4, 2009 13:12:13 GMT -5
That certainly looks like jade to me, but it can be hard to ID jade by visual inspection alone. The best way to tell is to measure the specific gravity of the specimen. Nephrite jade will have an SG of 2.9-3.1 typically. This method isn't foolproof either, because there are other materials that have a similar SG, and nephrite that isn't homogenous may be above or below that, depending on what material the inclusions are made of, and what percentage of the total volume of the material the inclusions make up. As for the magnetisim...jade itself definately isn't magnetic, even the black jade with a high iron content. However, depending on where the jade is formed, it may have inclusions that are magnetic. Is the whole stone magnetic, or does it have areas that seem more magnetic than others? You can try the scratch test...take a steel knife and see if you can scratch it...jade is tougher than steel, you won't be able to scratch it with a steel blade. Here are some photos of a few of my jade specimens that look similar to yours....   |
|
|
|
Post by akansan on Apr 4, 2009 21:16:29 GMT -5
I have a poor picture of the Porterville Jade. The top slab. You can kinda see the magnetite inclusions separating the light green from the dark green/black.  I'm not really sure where the slab is now, so I can't retake the picture. I know it's missing a slight chunk off the bottom.  Here's a bad picture of the cab from it:  |
|
southforkmining
spending too much on rocks
Member since October 2006
Posts: 275
|
Post by southforkmining on Apr 4, 2009 21:32:44 GMT -5
Hi guys..thanks for the input..Mikes...I tested it with hardness pics...mostly 6 does not scratch it...and 7 will........although in an area where it looks like some metal ( my guess is manganese, it will scratch with a 6 ).....and seems to be evenly magnetic all over it..it is mostly black with green tints and some green blotches...at first I though some type of black jade...but then the magnetic factor did not fit..Alaskan...thanks for the pic of Porterville jade...it does not look like that...and this definetly has what looks like irredesence or a sheen to it......pretty cool......I collected a couple of hundred pounds today.....just for a stash.........anymore guesses......thanks to all...Rich
|
|
MikeS
fully equipped rock polisher
Member since January 2009
Posts: 1,081
|
Post by MikeS on Apr 4, 2009 21:58:43 GMT -5
Jade has a hardness of 6.5....so if you are not scratching until 7, you are in the right area there...just based on its appearance, I'm going to go out on a limb and say it's probably jade with a lot of magnetite or something similar in the jade matrix....
|
|
MikeS
fully equipped rock polisher
Member since January 2009
Posts: 1,081
|
Post by MikeS on Apr 4, 2009 22:31:26 GMT -5
......I collected a couple of hundred pounds today.....just for a stash Another clue might be to look at the fracture of one of them...since you have a lot....  Take a hammer and break one open...jade will usually have a waxy, layered, felted, sometimes fiberous appearance...here are some pics for comparison...     |
|
southforkmining
spending too much on rocks
Member since October 2006
Posts: 275
|
Post by southforkmining on Apr 5, 2009 0:10:49 GMT -5
|
|
southforkmining
spending too much on rocks
Member since October 2006
Posts: 275
|
Post by southforkmining on Apr 5, 2009 1:41:30 GMT -5
Here are 2 small cobbles I polished today from this new material   and this is from a different deposit..I am searching for...this is a matrix of vesuvianite and other minerals...Rich  |
|
Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,492
|
Post by Sabre52 on Apr 5, 2009 9:59:52 GMT -5
Howdy Rich, Here are a couple of pics of the only cut blocks of Porterville Jade ( from the Janoko Mine) that made the cross country move with me. The black areas are magnetite rich inclusions and the bright green areas tend to be a bit more chromium rich, The white skinned piece was dug and the other with the more red skinned was from the surface, hence the rusting effect form the iron on the outside. Sorry about the saw marks. That stuff is tough to cut. I think the specimen Akansan posted is actually Victorville Jade from the Stoddard Wells collection area rather than Porterville ( lots of folks mix the villes' up). Both are nephrite but the Victorville stuff tends to be blacker and has much more pronounced crystalline areas of magnetite which some folks even gold electroplate.....Mel   |
|
southforkmining
spending too much on rocks
Member since October 2006
Posts: 275
|
Post by southforkmining on Apr 5, 2009 11:49:40 GMT -5
Hi Mel...thanks for the pics...I will have to cut a piece of this stuff, and break one...to get a little more info..thanks for the help..........Rich
|
|
MikeS
fully equipped rock polisher
Member since January 2009
Posts: 1,081
|
Post by MikeS on Apr 5, 2009 11:52:09 GMT -5
southforkmining- those do look like jade in many respects...I'm not sure about the specimen in the second photo, that's kind of an odd color for jade, reminds me personally more of serpentine, but then again color is never a reliable indicator of jade...have you measured the specific gravity of any of them yet? Although with that much magnetite in them, that may not give you an answer either... |
|
|
|
Post by akansan on Apr 5, 2009 11:55:23 GMT -5
Whoops! I'll verify that this can be electroplated, so I guess I'm from the other 'ville. |
|
southforkmining
spending too much on rocks
Member since October 2006
Posts: 275
|
Post by southforkmining on Apr 5, 2009 13:18:51 GMT -5
Mikes........I do think the piece in photo 2..was a little softer...in the field...my knife did scratch it some........there is serpentine here everywhere.....and usually the knife will easily scratch it...the piece in pic 2......barely left a mark..so it could be a serp that is a little harder than most..I have not done SG....tests...I always feel like I get no real answers from them..because everything up here seems to be a mix...nothing is pure...it the SG numbers always seem to overlap into another mineral that is also here.....thanks for the help..Rich
|
|
MikeS
fully equipped rock polisher
Member since January 2009
Posts: 1,081
|
Post by MikeS on Apr 5, 2009 13:47:23 GMT -5
I hear ya on the SG...unless the material is pretty homogenous, it's not as reliable of a test...I've found many specimens (particularly the darker material) that pass every other test, ie scratch, streak, matrix structure, visual inspection, the good 'old timer's hammer "ring" test, ect, but come in a bit off on SG due to the lack of purity...but it's a good test when the material is pure...
|
|
Wolfden
fully equipped rock polisher
Member since November 2007
Posts: 1,368
|
Post by Wolfden on Apr 5, 2009 13:57:50 GMT -5
Stupid question time .... what's the " SG " test ?
Wolf
|
|
MikeS
fully equipped rock polisher
Member since January 2009
Posts: 1,081
|
Post by MikeS on Apr 5, 2009 14:04:33 GMT -5
specific gravity...you take the dry weight of the rock (D), then suspend the rock in water and weigh it that way (W), subtract the two, and divide that into the dry weight... D/(D-W)...that will give you the SG, which is how much more a substance weighs compared to an equal volume of water...
|
|
Take a hammer and break one open...jade will usually have a waxy, layered, felted, sometimes fiberous appearance...here are some pics for comparison...
