|
|
Post by vcubitt on Apr 27, 2012 21:43:47 GMT 10
Hi, I am hoping that someone may be able to help me identify a mineral that I have found in a quartz vein. I have a quartz vein visibly running east-west for at least 200m on the surface and noticed part of it appeared very rusty when I chipped it. On the surface, the quartz looks like examples of hydrothermal quartz on google images. This kind of vein is supposed to be good for mineralisation and gold, I believe. When I attacked the rock with a pick, the quartz came out criss crossed in all directions by small and large veins of this grey metallic looking material that is considerably heavier than the quartz that contains it. It appears rusty and when I scrub it with the wire brush, it produces bright almost blood red paint-like colour. This seems to be the colour inherent in the material rather than rust coming off it as the colour continues even after I have scrubbed off what I thought was rust. I have taken several kilos out of the ground already and the veining continues sub surface - perhaps 1/4 of the rock is this grey material - I will follow the veins as far as can with a pick to see what else comes up. There is a gold, silver, lead and zinc mine not far away, <2km. I thought to pan some of the decomposed material around the hard rock and the first two out of four pans showed specks of gold. I am cautious of that result, as I was using the same pans and buckets not long before on the Shoalhaven River and found gold - might have missed some. I will wait to see if any future pans show colour. I am hoping someone may recognise the material. I am thinking some type of sulphide, lead or iron, or iron pyrite. I have no idea other than images on Google to compare with. The material does not respond to my metal detector (only a gold snoop I'm afraid) and it does not seem to be magnetic. The photos attached are a sample from a large vein. Would appreciate any responses. Thanks.        |
|
|
|
Post by rc62burke on Apr 27, 2012 22:07:37 GMT 10
Hi
It looks like ironstone to me, but then it should be magnetic, it could be Tin which will not be magnetic & wont signal on a detector, do more sampling if you think you got aspeck or 2, give the stuff a bit of a scrape & see what it shows
Lee
|
|
hereskip
Sluicer
I'm an agent of satan but my duties are largely ceremonial
Posts: 239
|
Post by hereskip on Apr 27, 2012 23:06:17 GMT 10
maybe only just a guess but non magnetic, could it be hematite? I'm really only guessing as its not quite silver enough for that.
Cheers skip
|
|
|
|
Post by Ric on Apr 28, 2012 0:08:02 GMT 10
My computer monitor is just about shot so it's hard for me to make out the colouring properly. At first glance it looks like Ironstone however when you mentioned the blood red colour I immediately though of Red Jasper which can be associated with quartz veins and gold. Here is a link to a thread from a few years back alluvialgprospectors.proboards.com/index.cgi?board=general&action=display&thread=405&page=1And a photo I took of some bits I have. See below  |
|
|
|
Post by stack992 on Apr 28, 2012 8:22:33 GMT 10
Its definetly ironstone probably hematite and the red color that leaches out of it is oxidised iron,and the fact that its not magnetic is explained by the iron content it would probably have to be in the range of 70% Fe content to be magnetic,most hematite on the east coast is of low grade,Which means its definetly not magnetite which is another mineral with Fe content but needs a lower Fe content to become magnetic the magnetism is caused by a combination of trace elements and Fe content.
Or I could be wrong and all the above is just bull$$$$.
|
|
|
|
Post by donnybrook on Apr 28, 2012 9:06:10 GMT 10
The Grey would most probably be sphalerite (forgive spelling) zinc ore. Do you get a sulphur smell when cracked with a pick? Many metals come in the form of sulphides gold etc. I went through the old mullock heaps at Sunny Coner years ago and found similar rock. Crushed it,tabled it, and then furnaced . The zinc expelled as a white plume as it has a low boiling point. Still had metal left at a higher temepreature. You should be able to crush a small sample and a roast to convert the suphides then weigh and clean it up with hydochloric acid. Very interesting.
donny
|
|
|
|
Post by vcubitt on Apr 28, 2012 9:28:47 GMT 10
Hi all, thanks for the suggestions. I should have mentioned the grey mineral is uniform colour throughout the veining but for the red oxidised areas on the outside.I have actually noticed a smell when I am breaking the material up but l wasnt able to identify it, didnt seem sulfurous to me, but not 100% on that. Donnybrook - when you treated your similar material, did you get gold out of it? Would you expect visible gold or? Thanks again.
|
|
|
|
Post by donnybrook on Apr 28, 2012 13:10:22 GMT 10
Yes I did get gold but it was only a small amount of ore. The old fellas did not miss much and they threw out what was considered worthless. The sulphur smell is like that of a firework having gone off. Apart from the zinc there was also another light coloured metal with a smidgeon of gold colour. We don't have native silver here (but I stand to be corrected) its in the form of a black oxide which you must reduce in a furnace by adding flour(carbon) to your fluxes. It sounds like you are onto something worthwhile. It needs an assay. Again very interesting. I would use this method :-
If you can crush say 500 grams into powder. Weigh it then add hydrochloric acid to it. You can only use Crown Corning Ware dishes or laboratory gear if you are going to gently boil. Gently because when the pH drops back to 7 the zinc will precipitate out all of the metals taken up with hydrochloric. This acid will not take up other base metals apart from iron etc. When boiled and cool use one of those full plastic sieves you can buy at Target after laying about twelve tissue papers in it wetting as you go. It should sit firmly on a 20 litre plastic bucket. Then pour your solution through slowly. Flush your dish with distilled water and empty remaining fluid. Gently spoon out the remaining ore onto your sieve. Then over your dish remove the papers and ore and dry it. Re weigh and see what losses you have had. If you wanted to furnace this you would need to clean and neutralize the ore with Ammonia. Cloudy ammonia at the supermarket will do the job.
The above method is also used to test for uranium. To your solution you add oxalic acid and if uranium is present it will drop as a yellow powder (Yellow Cake). The other thing hydrochloric will do is take up some silver (nitric is the main acid used) which is why I suggested distilled water as chlorinated water will drop any silver as a white powder.
donnybrook
|
|
|
|
Post by stack992 on Apr 28, 2012 13:10:33 GMT 10
me thinks you require a professional assay for under $100
-second guess a fine grained basalt with 'NO VISIBLE SULPHIDES' baron of any precious metals or perhaps just in the PPB,not worth digging catergory.
DISCALAIMER-I COULD BE WRONG AND ALL THE ABOVE COULD BE JUST BULL$$$$
Donny I put 10KG of Au that I could be wrong.
|
|
|
|
Post by vcubitt on Apr 28, 2012 15:45:12 GMT 10
Hi, Just been out digging enough rock and surrounding mud to fill a 20L bucket - panned and no visible gold, so methinks the gold I panned earlier was from other trips I apparently didnt clean up properly.
I crushed some of the grey metallic ore and it crushes to a red powder. Some of the larger pieces I put under a butane/propane torch and the pieces glowed red like a metal would (I wouldnt imagine mere rock would glow red from a blow torch, is that right?) No smoke came off the ore, it just glowed red.
I am digging deeper, and the quartz is getting more dirty the further I go, with red, black and brown veins and inclusions through it. Unfortunately no yellow veins, but Ill keep going while the rock responds to my pick. Donnybrook Im not sure about the smell, but there definitely is a strange smell when I strike the rock with the pick.
Does anyone know how I go about getting a sample assayed?
Thanks again.
|
|
|
|
Post by stack992 on Apr 28, 2012 16:15:05 GMT 10
try genalysis.com.au or just google mineral assays and your state,you should be able to get it done for a $100 or so and will probably take a month.
|
|
|
|
Post by donnybrook on Apr 28, 2012 16:51:12 GMT 10
Go by what Stack has said. Get it right and do your calculations eg each cubic metre of material (average) weighs 1. 6 tonne. Assay mate. Look at what you have and ascertain whether it is going to be economical Because you will probaly need a jaw cusher then hammer mill etc. Spend the $100 but I say you need a represemtative sample that is you need to get a lot (lets say 100 kilos) crushed then cone and quarter. Prepare it and put it on a tarp and roll it and roll it until you have a cone.
From each quarter (this is a failproof method) take one spoon or a shovel full. These four samples will give you upon assay the correct result.
Stack knows his stuff.
donnybrook
|
|
|
|
Post by Ric on Apr 28, 2012 17:29:55 GMT 10
Hi vcubit
I certainly don't have the experience and expertise that Donnybrook and Stack992 and some other members do and my thoughts could be totally incorrect but you have mentioned a metallic grey rock that crushes to a RED dust.
The pieces of jasper I have can look metallic grey with no sign of red at all depending on the light. You can see this in the top left of my photo above.
Could it possibly be Cinnabar? Again I'm only grasping at straws and have never seen cinnabar in the flesh, but again it can be associated with or imbedded in quartz.
Ric
|
|
|
|
Post by donnybrook on Apr 28, 2012 18:06:22 GMT 10
Cinnabar not Galena Lead,
( Cinnabar) as I have seen was at Windeyer near Mudgee. Anyway lets run on Stacks advice. It could have been a leader to the main deposit. It might not have been worthwhile. To me it would have been an experience to have found it. Have a look prepare the sample properly.
donny
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Apr 28, 2012 20:04:59 GMT 10
What stack said is spot on I reckon. Easy way to tell is a scratch test on porcelain, hematite will scratch red, jasper will scratch white, just depends on the iron content.
Diggerdude
|
|
