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geowizard 17:29:51 Sat Sep 8 2012 |
 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 |
Marshall |
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dickb 16:36:30 Sun Sep 9 2012 |
Dickb :smile: |
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geowizard 01:39:09 Mon Sep 10 2012 |
 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 |
More about Kimberlite deposits: http://sioviz.ucsd.edu/~fialko/Assets/PDF/khazan_fialkoG305a.pdf |
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dredger 05:58:38 Sat Oct 6 2012 |
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 |
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 |
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 |
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 |
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 |
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 |
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dredger 05:27:43 Mon Oct 8 2012 |
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dredger 05:57:47 Mon Oct 8 2012 |
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overtheedge 06:07:21 Mon Oct 8 2012 |
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 |
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 |
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 |
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 |
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growler 19:52:24 Mon Oct 8 2012 |
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dredger 23:58:27 Mon Oct 8 2012 |
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 |
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 |
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dredger 00:00:31 Wed Oct 10 2012 |
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 |
  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 |
no1,  no2,  testing. |
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growler 00:47:21 Wed Oct 10 2012 |
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BobAK 01:30:28 Wed Oct 10 2012 |
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dredger 02:04:41 Wed Oct 10 2012 |
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 |
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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dredger 06:44:28 Wed Oct 10 2012 |
QUARTZ,Including varieties Agate and Chalcedony Silcone dioxide Hardness 7 Crystallized quartz is very seldom Fl: however, the agate and chalcedony varities will often fl green or yellowgreen, back asap, |
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dredger 01:46:39 Fri Oct 12 2012 |
I have recoloured the previous pics 1 and 2 to show best i can, what I do see when using my uv light today, (1)  (2)  testing |
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geowizard 02:49:03 Fri Oct 12 2012 |
dredger, that is cool! What are your thoughts on the different colors and how do the colors relate to types of gemstones? Maybe I missed something? I will re-read the posts. |
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BobAK 05:10:13 Fri Oct 12 2012 |
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dredger 05:28:49 Fri Oct 12 2012 |
:confused: I don't know much about types of gemstones, but I think only Diamond opal and Amber are the only one listed in the uv light booklet, I think uv light reacts with other Gemstones and glass or minerals containing uranium but have feeling I know too little more to comment,we know from the hand book. 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 colours 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 wavelengths of visible light. the blue-white colour of a fine diamond is often enhanced by daylight fluorescence. Unquote, Which does not say the quality of the diamond " can " be determined by uv light, ?? and nowhere in the booklet says much about quality of anything,??. Also I heard a voice from somewhere that man made diamonds do " not " glow, no sure about though, cause the only diamonds i would look for would be from a river, Opals do glow well, and at this time opals are recovered from the opal tailings mounds by or on a conveyor belt below uv lighting, they are finding plenty of good opal thrown away by the old miners, or walking around the mining sites at night, with a uv light in u hand, but u have to watch out for the open shaft in the darkness, :smile: I think the real benefit here is the situation that I found myself in, many years after I started gold panning I was not aware of diamonds in the area, I did not know what they look like, and I found them when I used uv light, and did not know anything or do anything cause I did not know the value that was and is there ,until I looked on e-bay, :confused: Back soon bob,:smile: |
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dredger 06:05:49 Fri Oct 12 2012 |
so you are seeing the same colors that I see.very good, u kick me in the guts when u said," but I don't understand why there are not larger pieces of the same material ", exactly what I have wondered for many years, :smile: Do u suspect Diamonds, ??? |
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BobAK 03:51:57 Sat Oct 13 2012 |
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dredger 21:33:06 Sat Oct 13 2012 |
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BobAK 03:52:07 Sun Oct 14 2012 |
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dredger 04:58:11 Sun Oct 14 2012 |
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Diamond_digger 18:37:58 Mon Oct 22 2012 |
Diamonds do fluoresce blue. I shall try to explain a bit more. How to identify a diamond in the field. If you can do buy a hand-held electronic diamond tester. It is relatively easy a few things to remember. 1) All diamonds have a natural oily layer on them that repel water. 2) A diamond does not get hot 3) It is a crystal and many have triangular shapes on the sides. 4) It can be any color but it will have the same characteristics 5) All diamonds have a very special shine to them in their uncut state one you will never forget once you have seen one. 6) Carry a 10 x loop (Magnifying glass) with you it helps to show the inside of the stone and usually there are maybe one or two spots in them or a small shift in the crystal itself. 7) The usual diamond shapes are: Octahedron, Dodecahedron, Cubes Whole and Irregular Shapes 8) A diamond does not get wet so blow your hot breath on it and there will be no moisture on it. 9) Place the stone on a newspaper if it is not completely cloudy. Try seeing the print through the stone. If you can read the print or see it clearly, the stone is likely a fake. This test can have mixed results if your stone is very cloudy 10) Scratch the surface of a small compact mirror. A real diamond should have no trouble scratching your mirror. You can also try rubbing the stone with sandpaper. A real diamond should not be scratched Rough diamonds that are modified forms of the octahedron, dodecahedron and cube and display both rounded faces, points and ribs are referred to as whole diamonds. If the same conditions prevail and the rough is elongated its known as an irregular. These shapes are common to river bed and alluvial placer deposits reflecting the rounding of edges that occur through weathering and transport from their surface origin to the place where their found as a placer deposit. Hope this helps. Andy |
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geowizard 18:41:16 Mon Oct 22 2012 |
I am glad you found this thread! You're a great resource on this subject! - geowizard |
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Diamond_digger 19:01:06 Mon Oct 22 2012 |
A little more diamonds also fluoresce blue, then yellow, orange, green and white. It all depends on the color of the stone. However some diamonds do not fluoresce. So this is not a standard you can hold for all diamonds. The pure diamond does not fluoresce it is the impurities in the stone that does. As soon as I figured out how to put pictures on I will show a bit more. Below is a standard diamond grading scale for those lucky ones that find a big stone! The Color grading chart Color Description D E Colorless diamond F G H Nearly colorless diamond. Appears colorless when set into a piece of jewelry I J K L Faintly-tinted diamond. Usually yellow tint. M N O P Very lightly-tinted yellow diamond. Color is visible to the eye. Q R S – Z Light yellow diamonds. Color is very visible to the eye, even when set into jewelry Andy |
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leonard 16:54:09 Sat Oct 27 2012 |
Well, I've held a few. These were found at Crater of Diamonds in Arkansas. Not by me though, darn it! These are real! I like the yellow the best.  Leonard |
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Diamond_digger 17:28:21 Sat Oct 27 2012 |
Depending on a close inspection those stones are around $1200 not bad for a day out. I hear several big companies have tried and failed to work that pipe over the years. I cannot help but cringe... Put me and my gear on it and someone will retire Dude! Great picture! Andy |
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leonard 19:55:27 Sat Oct 27 2012 |
Whats funny is seeing this at the entrance to a state park.  Kind of like the picture I have of my truck with a 4" dredge in the back parked in Yellostone Park. Leonard |
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Diamond_digger 21:37:37 Wed Oct 31 2012 |
Andy |
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leonard 23:22:43 Wed Oct 31 2012 |
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