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Post by bunyip on Nov 14, 2008 14:58:40 GMT 10
Barite mines are scattered through the area also,from Tuena/Trunky through to Neville. some barite speciemens I have here look like native tin,Possible you could have that also.Bunyip
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Post by araluen on Nov 15, 2008 12:01:37 GMT 10
G'Day Bunyip
Yes barite does exist in the area and it is also associated with the volcanic hot spring deposits that formed on the old sea floor and are responsible for jaspers, and cherts and copper-silver-lead deposits. They form what is called facies from one to the other along strike. That is as the old black smokers on the sea floor were expelling clouds of material that became the base metal deposits, further out from them and in colder water you would get barite and then cherts of which jasper is just an iron rich variety. As for native tin - that is so rare that I have never heard of it (that does not say it does not exist though) Tin forms generally as cassiterite or tin oxide - it is a red to brown lusterous mineral with no metallic look to it. Tin can more rarely occur as stannite a copper, iron, tin sulphide which is a black to grey mineral that sometimes has a metallic look to it - it is quite rare though and I only know of it occuring in the region at a little mine near Bungonia. Many barite veins in the belt from Goulburn to the north have associated galena and sphalerite as well as minor specular hematite and rarer silver minerals.
Araluen
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Post by bunyip on Nov 16, 2008 17:06:42 GMT 10
Native Tin is a very rare mineral Arauen Looks very similare to Barite in appearance noted from a speciemen I have here (Barite) and and a photograph of the Native tin. Color is white to gray. Luster is metallic. Transparency: Specimens are opaque. Crystal System is tetragonal (below 13.2 degrees C tin converts to isometric). Crystal Habits include grains in placer deposits and lab grown specimens. Cleavage is indistinct. Hardness is 1.5 - 2. Specific Gravity is 7.3 (heavy even for a metallic mineral). Streak: white - gray.Native tin (the latin word for tin is stannum and gives tin its chemical symbol Sn) is a rare mineral. It is so rare that it in no way can it be thought of as an ore of tin. While I was researching what I had found about ten years ago (Barite) which I had no idea at the time what it was, the closest ID I could come up with at the time was "Native Tin" until I read of it's rarety I dismised it as being such.a lot more searching revealed "Barite". I was slightly dissapointed thinking I had found a rare mineral Anyway Barite I have from the District in discussion is very similare in appearance to Tin,Other Barite speciemens can be quiet interesting especially ones that come in crystal form...Bunyip
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Post by bunyip on Nov 16, 2008 17:13:35 GMT 10
Conformation of Native Tin The identity of the mineral has been confirmed both by r-ray and spectrographic means. X-ray photographs of three samples were taken; two from one polished section and one from another from a difierent vein. The three photographs are identical with a master photograph prepared from refined tin. One of the samples studied with r-rays was analyzed spectrographically by conventional D.C. arc methods and proved to contain only tin with traces of copper and silver. Approximately fifty grams of vein material were pulverized, leached with HCI and evaporated to dryness. A spectrographic analysis of the residue again confirmed the presence of tin. Native tin associated with cassiterite has been found in gravel deposits from several localities. To the writer's knowledge native tin in situ has not been reported. Its presence indicates a reducing environment. free from iron, sulphur etc. at the time of formation otherwise cassiterite or some other compound of tin would have been formed. The sequence of deposition of the vein minerals appears to be as follows: minor calcite and quartz; hematite, pitchblende and pyrite; late calcite and hematite.
A bit more on Native Tin...Bunyip
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Post by araluen on Nov 17, 2008 10:56:47 GMT 10
G'Day Bunyip
Well there it is then - never thought I would hear about that sort of thing. Well done.
Araluen
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Post by MrsFly on Nov 26, 2008 19:55:46 GMT 10
Hi Araluen,
How would you like to post a list of all known rocks associated with gold.
Then we could use Joe's link to look the rocks up.
I think it would be of great interest and very much appreciated by our members. ;D
Cheers
Mrs Fly
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Post by Ric on Nov 26, 2008 20:39:38 GMT 10
I'll second that request Mrs Fly Will be a very helpful tool for everyone. I have an article on looking for indicators somewhere. I'll see if I can dig it up. Ric.
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Post by araluen on Nov 27, 2008 15:42:40 GMT 10
OMG Mrs Fly, that would be an incredible task. I have a five volume series on the geology of gold deposits, each of which is around 500 pages long.
Best thing to say is still the old timers saying and that is gold is where you find it. It can and does occur in almost every rock type and that depends of timing, location and the rest of the geology in the area. For example, gold in WA is largely confined to basalts with banded ironstones second and lesser occurences in ultrabasics and acidic rocks whereas the basalts in eastern Oz are not regarded as terribly prospective at all. The Coolgardie rocks that contain the majority of the gold there are in a unique rock type generally not found anywhere else.
The only largely constant is that quartz veining is associated with the majoriity, but by no means all, rocktypes. It really depends on a couple of things and that is fluid flow that contained disolved gold and a structural mechanism to alow the gold to precipitate out and that in turn depends on the temperature and pressure at the time of formation. Then you get deposits like the Witwatersrand in South Africa (where I worked for a time) and that has no relationship to almost every other gold deposit in the world and it contains the majority of the world's minable gold. You can also get gold in carbonates as in Carlin the USA and that deposit type is also found practically nowhere else in the world, or the giant Sukoi Log deposit in Russia which is just a huge shale hosted deposit - noone really knows what that on is at all.
Sorry I can not be more help - really nead location specific details.
Araluen (once a geologist but no more due to American bankers)
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Post by firemanden on Dec 4, 2008 1:36:26 GMT 10
I have collected rocks from dads place outside of Mudgee which look exactly the same as the ones you have posted the pics of.
Have always wondered what they were!
Den.
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Post by bunyip on Dec 4, 2008 20:24:27 GMT 10
Good Tip Joe Thats using ya Knoggen Mate ........Bunyip
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Post by MrsFly on Dec 5, 2008 20:41:37 GMT 10
JoeS, "Killing hair growth" If you ever give up golding, I hear ZZ Top could do with another member. Hic Mis Rly PS: Sorry, I'm just sampling my Christmas order from Brown Bros. Nice drop! ;D
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Post by MrsFly on Dec 5, 2008 20:45:02 GMT 10
PPS: No offence Joe - they are one of my favorite bands. That gives me an idea - think I'll start a new thread. ;D
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kiwijw
Sluicer
Gold is where you find it & where she be there she be & where she be aint I
Posts: 109
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Post by kiwijw on Jan 2, 2009 10:13:29 GMT 10
Better late than never.....Yep I would say deffinitly Jasper. We have mountains of the stuff here in the Coromandel (NZ) & I have bucket loads of the stuff as well as rock gardens full of the stuff. I find HEAPS when out fossicking the Coro for gold. Looks beautiful when wet & in the river. Really stands out & being a magpie I can never walk past a piece when I come across it which is usualy every time I go out Polishes up in a rock tumbler beautifuly. Take care JW
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