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Author Topic: Need an expert identification....  (Read 8945 times)

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Offline diamond jim

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Re: Need an expert identification....
« Reply #10 on: November 04, 2014, 08:13:14 PM »
Well, you're at least one-up on me. For all the effort I've put in, I've yet to see my first diamond, though I haven't used a microscope. I have few regrets. It's been a great learning experience. If you ever plan on being up this way, I hope you'll let me know. Would enjoy some prospecting with you. I'll keep you posted on my trips, and the results...good or bad. I'll probably have more questions for you, too...ha
Jim

Offline EMF

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Re: Need an expert identification....
« Reply #11 on: November 05, 2014, 08:37:03 AM »
It would be fun to meet up and trade stories, check out some ground. Keep me posted on your activities. I like nothing better than prospecting in geologically understudied places with some potential for unexpected results. That diamond I found was a surprise, and its presence raised some serious questions for me about the geology of its origin.

 I was just giving some black sand heavies a close study with the microscope to try and understand the mineral environment that some gold was associated with and there it was, with that double pyramid shape with sides rounded out enough to make it almost spherical, with evidence of some erosion on its way up from below. . It came from an area with a high preponderance of ultramafic rock.

In those early days I got a little careless after I found it and I failed to notice some critical differences between diamond and zircon crystals, and thought when I found all these zircons that I had found this huge microdiamond deposit. I got a little too excited, which led to some embarassment later. Lesson learned. This discussion has me wanting to do a more thorough examination of the sample I found the diamond in. They are usually far and few between in any deposit, and any more in that sample would be very anomalous.

Offline diamond jim

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Re: Need an expert identification....
« Reply #12 on: November 05, 2014, 01:44:52 PM »
I'd like to see you get back in there and track down the source. Sounds like you may be on to something. Keep us posted on the forum, and I'll do the same. I'm hoping I'll get a chance yet this fall. Weather is good right now. I just finished standing the 20' x 8" stack for my wood stove in the shop. I need to anchor the bottom, and then get a guy with a portable welder to weld the pl;ate on the outside. I've already got all the inside welding done, so once the outside is done, I can go prospecting again...maybe next week, if the weather holds.
Jim

Offline EMF

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Re: Need an expert identification....
« Reply #13 on: November 05, 2014, 03:53:01 PM »
Hopefully I'll be back to prospecting in the spring. I'm recovering from a difficult illness that stopped me since the end of 2011. I have a lot of things to repair and take care of that I had to neglect while sick and I'm making good progress there. The most I could do when I was down was go over my field notes, study more geology and my mineral samples, and work out some of the geological problems pertaining to the vicinity of my claims, while making plans for mining and prospecting some good spots I found. I never stopped dreaming; I just had to let the body rest and heal. Winter will impose some time for thorough preparation.

Offline diamond jim

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Re: Need an expert identification....
« Reply #14 on: November 05, 2014, 07:24:49 PM »
Well, all the best. It's the pits being sick. Hope you have a good winter. As for me...I'm glad I'll finally have a woodstove in the shop. I plan on building jig kits this winter. I'm also going to produce a unit for powering shaker, and wave tables. It gets cold up here. I live at 4500', and this far north it can get darned cold. When i was young I could put up with it. I'm almost 66, and putting up with it isn't much fun anymore...LOL. I have a large wall that absorbs solar heat, but that only works from about 11:00 AM on. The woodstove is to heat it up in the morning.
 If I get down to Nevada again this fall, I'll be in touch with the results.
Jim

Offline EMF

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Re: Need an expert identification....
« Reply #15 on: November 05, 2014, 07:44:30 PM »
It sounds like it you have the kind of built in life stresses that keep a person healthy and long-lived. Keep warm, and enjoy the projects. We'll be in touch.

Offline Denadii Cho

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Re: Need an expert identification....
« Reply #16 on: December 26, 2014, 11:56:47 PM »
It is tuff, ash and larger pyroclasitic fragments welded together by the residual heat of the eruption, and is most likely of the same composition as that of the surrounding igneous rocks of the same age.  However, you'll need to do further analysis to determine the possibility of it being a lamproite tuff. See what any geological maps show about the area where found, examine the rock sample itself for positive indicators of it being lamproite. Are lamproite pipes geologically possible where the rock was found? If the pipes are posssible and the rock is a lamproite tuff, then it is time to try tracing out the source of the rock and doing some dry washing for indicator minerals in the area. One way or another, tuff luck.


I have to agree.   Its definitely ash
Credendo Vedes    In believing, you see.

Offline NS Gold Seeker

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Re: Need an expert identification....
« Reply #17 on: December 27, 2014, 09:56:59 AM »
There were diamonds discovered outside of Wawa Ont a few years back and the different thing was,
there were no kimberlite pipes anywhere near.  The diamonds were in shield volcanics.
Not sure if your cratonic rocks are similar and likely not as old but the environment of deposition could be similar, worth a look.

The Wawa diamonds are unique in that they are being discovered in rock that is 2.7 billion years old, while the oldest kimberlite is only 1.2 billion years old.
“There have never been diamonds reported in rocks as old as the Wawa rocks ever – they are in a yet-to-be identified rock type,” said Wilson.
As a result of Clement’s find, the district geologist said, “There has been over $20 million worth of diamond exploration that has come to the Wawa area that probably never would have happened.”

Diamond discovery sparks exploration wave | Sudbury Mining Solutions
Gold is good.

Offline diamond jim

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Re: Need an expert identification....
« Reply #18 on: December 27, 2014, 04:52:29 PM »
There were diamonds discovered outside of Wawa Ont a few years back and the different thing was,
there were no kimberlite pipes anywhere near.  The diamonds were in shield volcanics.
Not sure if your cratonic rocks are similar and likely not as old but the environment of deposition could be similar, worth a look.

The Wawa diamonds are unique in that they are being discovered in rock that is 2.7 billion years old, while the oldest kimberlite is only 1.2 billion years old.
“There have never been diamonds reported in rocks as old as the Wawa rocks ever – they are in a yet-to-be identified rock type,” said Wilson.
As a result of Clement’s find, the district geologist said, “There has been over $20 million worth of diamond exploration that has come to the Wawa area that probably never would have happened.”

Diamond discovery sparks exploration wave | Sudbury Mining Solutions
Good info GoldSeeker, many thanks. I read the article. Going to do some more research on the geology of the Wawa find.
Jim

Offline NS Gold Seeker

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Re: Need an expert identification....
« Reply #19 on: December 29, 2014, 06:23:36 AM »
Here is a good description of the Wawa diamond belt.  It is hosted in a breccia and lamprophyre.

http://www.d.umn.edu/prc/lakesuperiorgeology/Volumes/ILSG_52_2006_pt3_Sault_Ste_Marie.cv.pdf


Description of the Diamond-bearing Rocks
The diamond-bearing breccia and associated lamprophyre is broadly distributed throughout Lalibert,
Leclaire, Menzies and Musquash townships. On-going mapping by Pele Mountain Resources Inc. on the
Festival property and by Nathalie Lefebvre on the GQ Property has helped to refine the classification of
these rocks. Systematic exploration and sampling suggest that the individual diamond occurrences are part
of a much larger suite of rocks and that diamonds occur primarily within discrete layers at the base of
diamond-bearing zones.
North-northwest-trending diamond-bearing zones of breccia and lamprophyre are up to 1500 m in length
and up to 800 m in width (Pele Mountain Resources Inc., press release, January 18, 2005). The breccia
forms thick units (maximum true thickness is approximately 110 m) dipping to the northeast 30°. The
lateral extent and thickness of the breccia unit is not well constrained, owing to the large-scale regional
folding and thrusting (Lefebvre 2004). Figure 3 provides a detailed map of the southwest corner of the
Festival Property showing a recent interpretation of these diamond-bearing zones.
The diamond-bearing rocks can be visually subdivided into two classes, lamprophyre (dikes and bodies of
indeterminate morphology) and heterolithic or polymict breccias. It is often difficult to differentiate
between the two classes since the lamprophyre dikes frequently contain an assortment of inclusions that
give them the appearance of breccia. The lamprophyre dikes cut the breccia units. Both lithologies have
been metamorphosed to upper greenschist facies.
The breccia primarily consists of angular, pebble-sized, lithic fragments, mainly of volcanic composition,
contained within a green to grey fine-grained matrix. The matrix grain size ranges from < 2 mm to 1 mm.
At least eleven distinctive types of lithic fragments have been observed in the breccia and the fragments are
irregularly distributed throughout the breccia. The clast population is primarily derived from rocks with
which the breccia is intercalated. Most typically these clasts are mafic and felsic metavolcanic rocks and
intermediate to mafic intrusive rocks. Other clast types include fragments of clast-supported breccia within
matrix supported breccia, fragments of earlier matrix-supported breccia with fewer than 5% fragments and
coated lithic fragments (Lefebvre 2004).
The breccia is characteristically massive, unstratified and poorly sorted with clast size ranging from sand to
boulders up to 9 m. Primary sedimentary structures such as bedding and crude grading are rare (Lefebvre
2004).
Gold is good.