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people online in the last 1 minutes - 0 members, 0 anon and 0 guests. (Most ever was 29 at 13:36:32 Sat Aug 3 2002) |
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geowizard 17:29:51 Sat Sep 8 2012 Offline posts Reply |
 What are a girls best friend? Geophysics can help find them. http://www.pdiam.com/s/Home.asp Check out the Chidliak project. BTW, most geophysical anomalies that look like a Kimberlite/Lamporite pipe are only gold deposits!:smile: Are there any of these in Alaska? - Geowizard |
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MarshallAk 16:30:11 Sun Sep 9 2012 Offline 879 posts Reply |
Back in the 80's I was taking prospecting classes in Anchorage taught by Leo Mark Anthony. One day he talked about minerals in Alaska and passed around a vial containing two raw diamonds that he said he found in Alaska. (but wouldn't say where). Both were small, and of the typical octahedron shape. I guess they are here...somewhere...
Marshall |
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dickb 16:36:30 Sun Sep 9 2012 Offline 102 posts Reply |
With Alaska's volcanic activity, it wouldn't suprise me at all.
Dickb :smile: |
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geowizard 01:39:09 Mon Sep 10 2012 Offline posts Reply |
Could this be a kimberlite pipe?
 Compare with the locations in this report: http://www.pdiam.com/i/pdf/chidliak189.pdf The image shown above is a small portion of a residual magnetic intensity survey done by Alaska DNR, DGGS GPR2011-2. The dashed lines outline one square mile for reference of distance. This type of survey shows geologic structure that is otherwise impossible to see because the area is covered by marshland, mud, gravels, etc. |
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geowizard 18:49:06 Mon Sep 10 2012 Offline posts Reply |
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dredger 05:58:38 Sat Oct 6 2012 Offline 2604 posts Reply |
OK, What could Angstroms have to do with Diamonds, ??. or gold, ??.or to the new guy who is just starting out, say he has just purchased a 6in dredge, never been under water and wondering if he was throwing away a big diamond, or even a few small ones, and how the heck would a new guy know if there were diamonds in this area anyway,??,any new guy should know from now on that Diamonds have a specific Gravity much lighter then gold, more like your average rock, meaning a gold sluice is not designed to recover diamonds, but, it is reasonable to assume that if diamonds pass through a sluice, there is some chance a diamond may be retained a little longer then most rocks, and if the sluice was shut down during this period, a or a few diamonds may be caught by chance,
Next Problem is identifying the diamond in among the rocks recovered in the sluice during/when panning out, :confused: So, after many years asking myself this question, I stumbled over my method, which I was satisfied, did give me a chance, Sorry have to run, family dinner, back asap. :smile: |
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geowizard 15:37:54 Sat Oct 6 2012 Offline posts Reply |
dredger,
You got me thinking - again!:smile: One of the important things to remember about diamonds and HOW to identify them is they WILL scratch glass. I haven't tried this - but you can probably take small, clear crystals from your pan cons and use a piece of glass to test for diamonds by rubbing the grains on the glass and looking for scratches! - Geowizard |
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overtheedge 17:30:17 Sun Oct 7 2012 Offline 600 posts Reply |
Quartz scratches glass.
I've tried scratching glass with a "cut" diamond and the difference is remarkable. The diamond really bites in. eric |
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Au_Seeker 18:18:17 Sun Oct 7 2012 Offline 209 posts  Reply |
If you suspect that there maybe diamonds in an area your dredging couldn't you put a grease plate at the end of your sluice, diamond if present should stick to the grease plate? Skip |
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dredger 02:49:04 Mon Oct 8 2012 Offline 2604 posts Reply |
G-day Geo, :smile:
Mate, I nearly cracked a rib laughing when I visualized me scratching a sheet of glass on the river, I would be nuts in minutes ,:smile: But as usual you are correctomoondo, ( correctomoondo meaning very correct,) and a great inspiration to us all with u post, when we can as you say, " get u thinking ":smile::smile: So here and now I suggest that no 3 (geo) method of identifying diamonds, in dredge cons, should be scratching on glass, Now u got me thinking,?? Thanks Hey overtheedge, I think the cut is a major factor yet to be explored,here is something of interest,?? Mohs hardness Mineral Chemical formula Absolute hardness Image 1 Talc Mg3Si4O10(OH)2 1 2 Gypsum CaSO4•2H2O 3 3 Calcite CaCO3 9 4 Fluorite CaF2 21 5 Apatite Ca5(PO4)3(OH–,Cl–,F–) 48 6 Orthoclase Feldspar KAlSi3O8 72 7 Quartz SiO2 100 8 Topaz Al2SiO4(OH–,F–)2 200 9 Corundum Al2O3 400 10 Diamond C 1600 On the Mohs scale, graphite (a principal constituent of pencil "lead") has a hardness of 1.5; a fingernail, 2.2–2.5; a copper penny, 3.2–3.5; a pocketknife 5.1; a knife blade, 5.5[clarification needed]; window glass plate, 5.5; and a steel file, 6.5 STEEL FILE 6.5 QUARTZ,7 MOHS, INTERESTING, G-day Au_seeker, I think the greased slick plate works best where there is only sand being washed the diamonds, like beach diamond recovery, I would suggest the bigger rock in my sluice/area would just nock or push the diamonds along and off the grease plate,????. In my area, I also think, because diamonds have a hardness factor of 10 on the hardness ( Mohr )scale, and a specific gravity of 3.5, suggest to me that diamond and rocks flow or travel together in the "erosion factors" down a river, "but the diamonds" being harder, wear less,???, so " may " stay larger /longer than other softer water worn rocks, But, diamonds can be worn or ground smaller, also they are usually “cut” with a firm impact, along a ?? Fracture line, then ground to shape required, for a girl’s best friend, My final whooper wild guess / theory based on above and very little other facts, (some of which i saw with my own little eyes,) Leads me to suggest that Mother Earth is laughing at us because she fractures larger diamonds into small diamonds (that have no more natural fracture lines left,(around 1/16")( the reason why diamonds do not usually fracture smaller 1/16" May be, is or has something to do with atomic bonding of diamond molecules, and their, crystal atomic molecular structure, I think,) guessing big time here guys, Meaning to me, that if you have allot of small diamonds in u dredge cons like me, may mean, a Kimberlitic pipe source of these diamonds may be close, or a long way away, depending on the length of the river,?? The reason being my guess is large diamonds fracture into smaller size diamonds quickly, perhaps over a few miles of river after leaving the source, so if a new guy who just brought a 6" dredge immediately found small diamonds using No1 method, and No 2method in his dredge cons, and after a few weeks of finding same, I would suggest he should move the dredge up the erosion zone, / river, until he begins to find large diamonds, if he is looking for diamonds close to the source, not gold, but why not do both,????? ANOTHER thought of mine while have to wait until later,?? Gotta go back asap. |
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Jim_Alaska 04:10:54 Mon Oct 8 2012 Offline 4302 posts Admin  Reply |
OK, You guys have me totally confused. But maybe my experience is unusual.
From reading what has been said, it would appear to me that you are talking about seeing diamonds already in a shape that we all recognize as a diamond. I have only seen two diamonds that came out of dredge cons and they didn't look anything like a diamond. I would never have recognized them as a diamond. This is because they were "encrusted" in some sort of something that looked like lumpy hardened mud. The closest I can come to describe what I saw was that they looked almost identical to a candy brand called "Boston Baked Beans". The candy has a coating almost identical to what I saw covering the diamonds with only one exception, the candy was red and the diamonds were brown. So I guess my confusion and the question I am asking is, "do diamonds usually appear all clear and sparkly like we get in a ring?" If they do, I have no idea what the diamonds I saw were covered with. They only revealed their true identity once the crust was broken off.
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dredger 05:05:56 Mon Oct 8 2012 Offline 2604 posts Reply |
About how big were they Jim, ??
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dredger 05:27:43 Mon Oct 8 2012 Offline 2604 posts Reply |
please.
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dredger 05:57:47 Mon Oct 8 2012 Offline 2604 posts Reply |
Jim, guys, go to e-bay rough natual diamonds for sale,:smile:
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overtheedge 06:07:21 Mon Oct 8 2012 Offline 600 posts Reply |
If I lead anyone to think I have held a raw diamond, I accidentally misled you.
As far as a cut diamond having greater bite into glass than a raw diamond, I don't think it makes a difference. The vast difference in hardness between glass and diamond is so extreme, it is comparable to gouging wet mud with a stick. The Mohs scale isn't relative to anything. Quartz is not 7X harder than talc (actual 100X). Nor a diamond 10X to talc (actual 1600X). See Vicker's scale or absolute hardness. Glass comes in somewhere around 60X compared to talc. Do a search for carbonado. If I ever saw one, I don't think I would ever suspect it as being a diamond. eric |
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dredger 08:43:36 Mon Oct 8 2012 Offline 2604 posts Reply |
http://en.wikipedia.org/wiki/Vickers_hardness_test
http://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardness The Mohs scale isn't relative to anything, interesting. reading it, ??. Jim, overtheedge mentioned carbonado, and I found a picture on e-bay, page4, could be what u have seen, ??. |
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geowizard 15:27:59 Mon Oct 8 2012 Offline posts Reply |
At the top, I provided a link to Peregrine Diamonds, Ltd. They are a diamond exploration company. Here's another link that shows more about how they explore and what a natural rough .99 carat diamond looks like. http://www.pdiam.com/i/pdf/Native-Inuit-Resource-Mag-March2012.pdf The photo of the diamond is about 3/4 of the way down on the pdf. Gemologists use a "refractometer" to check gemstones including diamonds. It uses light and measures the amount of refraction. I can see dredger now, going over the cons with a refractometer! :smile: |
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cubsqueal 18:37:12 Mon Oct 8 2012 Offline 365 posts Reply |
On the subject of diamonds passing through a sluice, most of us are probably aware of Keene's 5-inch diamond dredge with its 3-stage extended sluice box system for "increased recovery of gold and gemstones." If a person thought he could pick up a few diamonds while dredging, it might make sense to use a sluice like what Keene has already engineered as being capable of getting the job done. Maybe a person could just buy the sluice box? |
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eightymesh 19:50:45 Mon Oct 8 2012 Offline 222 posts  Reply |
an oscillating diamond grease pan
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growler 19:52:24 Mon Oct 8 2012 Offline 36 posts Reply |
This site has pictures of rough diamonds. The rough uglies (bort) can be bought cheap. 5 yrs ago I bought 20 1 carat stones for $100. Just for testing and such. http://www.diamondrough.com/rough/samples.html Jim
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dredger 23:58:27 Mon Oct 8 2012 Offline 2604 posts Reply |
Thanks Growler, your link of pictures show so many different shapes and colours really sends home the fact that there so many different types of diamonds, from so many different locations, and some that can be covered, or partly covered with another substance, wow. and the rough diamonds being sold on e-bay, wow,
Perhaps a new dredger could have the mindset that he has little chance of visually identifying diamonds in his area, but firstly rely on " the story of Fluorescence " An explanation of ultraviolet florescence and a descriptive list of fluorescent minerals, and a cheap ultraviolet hand held light, which is My no 1 " easiest method for identifying diamonds,on the river. (Personal thought here,) Darn and dang, I now wish I had known this info 16 years ago, I would be one of the biggest rough diamond sellers on e-bay, just the shear number of small under 1ct and half ct diamonds I have fluoresced in my cons, unbelievable, I thought they were pretty much worthless industrial diamonds, I could have been making more money out of diamonds then gold, and still got the gold, :confused: In Hindsight I should have been using a sluice as suggested by Cub, ( bit late mate, but thanks anyway )and a oscillating diamond grease pan as suggested by eightymesh, ( thanks eighty mesh ), Hey Geo,:smile: U never want to see want to see me going over my cons mate,( too much water wrinkled bum crack,), ha ha ha, Ok, my method, and the method I would use if I was running 6" dredge cons, method focus is not waste allot of time on recovery of diamonds but by first identifying the diamonds in the cons first, So, I collect, screen all materials, pan the big gold, and screen collect all fine cons/gold to be processed later, ect, and leave all or as much of the oversize panned waste back in the hole, like most dredge operations basically do, Now I do the same thing, except all panned of materials are collected and placed into extra tubes, so I keep all the gravels from each cleanout, Basically I would then position and drain the materials tubes until later that night, the darker the better, Then using a " versalume " by Raytech, “ultraviolet hand held lamp”, I would quickly pass the lamp over the oversize tubes of materials by running / pouring gravels across a board or slid and back into a empty tub, easy to do, Diamonds Fluores and are clearly and easyerly identified, basically because all the rest of the materials or gravels “ appear” very dark or opaque, ( in my area ) it is not allot of work, and in last years of operations, I found allot small diamonds, some of which I again tested with a Presidium Gem Tester, which also definitely indicated Diamonds, and again I thought they were not worth that much money at the time, The versalume light was about $100, and the gem tester was a few hundred $, Sorry got run, there is also another bit of info that has puzzled me big time since I got my ultraviolet light, tell yous soon, back asap. Dredger. |
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Jim_Alaska 01:49:29 Tue Oct 9 2012 Offline 4302 posts Admin Reply |
This is a link taken from growler's post. This is more like what I saw, although not exactly.
http://www.diamondrough.com/rough/r02_pages/r2_05.htm What I saw looked like it had a dried mud crust on it. It was about the size of a small lima bean, but shaped much like a football.
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trnelson 08:14:58 Tue Oct 9 2012 Offline 49 posts  Reply |
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dredger 00:00:31 Wed Oct 10 2012 Offline 2604 posts Reply |
A thought of mine here for the new guys is the pictures posted by trnelson, the two stones appear to have no or little wear, suggesting to me that were recovered close to the source,??
Please check out Jim's link and the diamonds shown, to me they look like stones I found in this sample,  I did get to roll them around when I looked at the sample, testing, |
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dredger 00:07:43 Wed Oct 10 2012 Offline 2604 posts Reply |
Two pics of a rough diamonds on e-bay,
  Next pic is of the same sample as above,  To me, they have the same appearance,different colour, :confused: The sample came from Nome Beach, can anyone tell me if there are diamonds at Nome, ??. |
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dredger 00:28:24 Wed Oct 10 2012 Offline 2604 posts Reply |
These are some stones ect, I found in my dredge cons that fluoresced under a hand held ultraviolet light,
no1,  no2,  testing. |
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growler 00:47:21 Wed Oct 10 2012 Offline 36 posts Reply |
Dredger, great find (I.D.). For all these are a good tool to ID a diamond (saves your wind sheild or mug) http://www.igem.com/Gemlogis-AZURE-Electronic-Diamond-and-Gemstone-Tester.html What is ideal for a dredger is save -1/2 and run over a grease table. Hi banker style w/ lo water flow. Test stones will prove table works. Keep in water when not in use! I like pink! Found none. What are prices for uncut colored stones you have seen! https://www.idexonline.com/index.asp Jimmy
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BobAK 01:30:28 Wed Oct 10 2012 Offline 696 posts  Reply |
Hi Dredger, what color did they fluoresce?? In my dredge cons I get some that flouresce yellow and some bright blue under short wave. Both appear to be clear or translucent little crystals
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dredger 02:04:41 Wed Oct 10 2012 Offline 2604 posts Reply |
No Worries Bob,
Quote, From the Versalume by Rayteck, portable ultraviolet lamp, hand book / bible,:smile: DIAMOND Native Carbon Hardness 10 Gem diamonds have been found that fl in a variety of colous including green,orange,red and blue, usually best LW. blue is the most common fl colour.Diamonds react well to the longest ultraviolet rays and even to shorter wavelenghts of visiable light. the blue-white colour of a fine diamond is often enhanced by daylight fluorescence. unquote, Sounds like u r on to it mate, This small 50 page book contains similar information about I think all other minerals that fl as well, 89 others, so if it does not fl like a diamond,check the book, :smile: |
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dredger 02:24:46 Wed Oct 10 2012 Offline 2604 posts Reply |
Good one Growler, and yes that is a good guide line method,
Mate, I think u best guide line for the type, colour, size,value is E-bay, because it is a good place to sell them, :smile: |
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