Native silver in quartz ?

Heath,
You've got the weight, if you can get the volume, you can get the specific gravity, SG, which tells a lot. SG of silver is @ 10, '10x heavier than water', quartz is @2.6. 2.7 is mica. If it is half silver, it should feel distinctly heavier than a quartz chunk of same size. If you have a measuring cup w/ marks on the side, submerge it in water, see the amount, remove it and see what is left. The diff. is the volume. there is a thread on how to get SG here on mindat too. That would be even better to consult.
Either way, this is only a ballpark figure, but if you're new, like me, (and underfunded like me!) it is a good start. You can only estimate the SG since you can't know the exact percentage of quartz you have. So if your SG is anywhere near 3, assuming it is half quartz, you have no Ag, if it is around 6, you may have half silver, half quartz. Or another heavy mineral is in there. Make sense??! Hope this helps!

Those last two photos remind me of Trinitite.

Has anyone written an article about hardness and SG testing that we could point people to?

Rock Currier
Crystals not pistols.

Jim Bean Wrote:
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> Those last two photos remind me of Trinitite.
Jim its the first ive heard of Trinitite, its all new to me but after reading up on it and viewing images i see what you mean, at first i thought it must be Flurite but then realised its far to hard it scratches steel very easily aswell as glass, it was dug from a previously unknown gravel bed i descovered while excavating in my local area. The beds are at least 15.000 years old, could the near by Cleveland dyke event have caused a simmiler enviroment in the rocks it intruded?

Thanks to all and sorry if ive not directly replyed to a post, ime still trying to take it all on board!

Rob Woodside Wrote:
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> Thanks for the new pictures. It is definately not
> Silver. Perhaps an amphibole? What is its
> hardness?
>
> Claire, why do think this is not flint?
> [www.mindat.org]
> ,filename=DV000061-001.JPG
> Heath says the purported silver does not produce
> micaceous flakes, I agree with you that it does
> look like some kind of mica..

Apologies for not getting back sooner, I am on night rotation for a few days. My reason for not thinking it was flint or chalk is because having seen the flint and chalk beds of the South Downs (GB), and also having some back at home, this peice does not look like it. However, I do not mind being proved wrong... The crystaline peice on the top appears white and looks like it has definate clevage lines, flint and chalk appear not to have these and are only cystaline under microscope. However, I do think it is an interesting conundrum.... Hope this helps!

Rob - Claire the geologists helping me have viewed the nodule and seemed quite sure it was flint, heres a pic of the other side, it does have some wierd looking stuff on the darker surface. and by what ive read are still not fully understood. ?

D Mike Reinke Wrote:
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> Heath,
> You've got the weight, if you can get the volume,
> you can get the specific gravity, SG, which tells
> a lot. SG of silver is @ 10, '10x heavier than
> water', quartz is @2.6. 2.7 is mica. If it is
> half silver, it should feel distinctly heavier
> than a quartz chunk of same size. If you have a
> measuring cup w/ marks on the side, submerge it in
> water, see the amount, remove it and see what is
> left. The diff. is the volume. there is a thread
> on how to get SG here on mindat too. That would
> be even better to consult.
> Either way, this is only a ballpark figure, but if
> you're new, like me, (and underfunded like me!) it
> is a good start. You can only estimate the SG
> since you can't know the exact percentage of
> quartz you have. So if your SG is anywhere near
> 3, assuming it is half quartz, you have no Ag, if
> it is around 6, you may have half silver, half
> quartz. Or another heavy mineral is in there.
> Make sense??! Hope this helps!


Mike i hope ive done this right if so the volume is 1070 ml so now how do i get the sg ?

6 lbs / 2.2 lb/kg = 3 kg = 3000 gm

1070 ml = 1000 cm³

3000 gm / 1000 cm³ = 3 gm /cm³

So specific gravity = density of substance / density of water = (3 gm/cm³) / (1 gm/cm³) = 3

So roughly (to 1 significant figure) the specific gravity of your "Ag" is 3. That is too low for a rock that is half Silver as Mike says.

Thanks for that Rob and hopefully i will eventually understand ! i would love this piece to be silver and quartz for obviouse reasons ! but i realy just whant to know what it is as it will help my research, and maybee fill one of the gaping holes ime having to jump across at the moment.

Mistaking shiny mica for silver or gold has been very common historically, so don't feel too bad about it. Read the great book "Roughing It", by Mark Twain. There's a funny chapter where he describes how he mistook a bunch of mica flakes for a rich gold deposit. And Silver Mine in Bear Mountain State Park, New York, is just a mica-bearing quartz locality. So you're far from alone, Heath.

Yes ive learned a lot being wrong as this is the only way, ime still not totally convinced its mica as it definatly does not have laminations of any kind when disturbed with a needle it just crumbles into a silver sparkling soft dust ?

Also can anyone tell me of a mica that scratches steel ? like this stuff ?

Quartz impurities mixed into the mica scratch the steel, not the mica itself.

Heath,
Try getting a few 'beginner' rock books at a library, and don't be ashamed they are for beginners, this is a deep subject, and get a few, because each will explain things a little different, and each will add to your awareness. I for one, never gave a second thought what is under my feet, and now it is a brave new world, in a good sense. And w/ book in hand, keep mindat on your screen when reading, to compare pictures, posts, etc. Very helpful. Enjoy.

Here is the link to the thread that discusses how to perfom SG tests. Yes, this seems to be a recurring request and would be nice if pinned somewhere. There are a few variations of the method, some being more technically accurate. But for smaller sized pieces and ease of execution, the method that Reiner describes is normally accurate enough to get a helpful result. The density information can then be found on the mineral data page for the mineral that you are trying to ID. So you can compare as above if the SG is in the correct range for your suspected mineral as in the silver above. If it is not close then you know you have something else.

[www.mindat.org]

Hope this helps.
regards,
stephanie

Thanks for all the help its been an eye opener for me, and please i hope ive not offended anyone i tend to question everything !

Hi Heath, I just read through this thread...the flint nodule is a typical piece of flint with a chalk "rind". It's found all over the east coast and southern England. Anyone heard of the White Cliffs of Dover? They are chalk (Cretaceous, I think) full of such black/gray flint, as are cliffs further north on the east coast. It is also found deposited all along the coast from ships' ballast and from undersea exposures, and has been dragged here and there by glaciers.

Heath, I'm curious about your research in the Cleveland area. What are you researching? Cheers, Becky

Hi Becky firstly the correct discription is flint burrow nodule and yes they are found in the south east of England, but as ive said not fully understood they are thought to be remnents of some of the planets eariest life forms. As for my so called research ime an ordinary man who decided one day that what he found beneath his feet did not match what it was said to be, then in the early days was patronised quite a bit by the experts but have now a year and a bit got them sitting in the shadows not quite sure what to say to me!

The more i look at this stuff the more ime convinced its not mica of any kind, its not layered in any way, also ive attempted cleaning it according to the native silver method on another thread and it has helped but is not doing a lot to the darker pieces, please could anyone who believes it or are sure its mica show me images of similer pieces ?