Electronic Prospecting in Silver Country

[Jim Hemmingway]

Hopefully this will make the banner soon.....

Hi Jim...what exactly does that mean? Forgive me but I have no knowledge of banner finds other than possibly they are interesting or valuable...

Jim.

 

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[Tuberale]

Hi Tuberale…your point is a good one. Calcite [CaCO3} ranges from white to creamy white but various impurities may result in almost any color…even black. For example, fluorescent pink calcite is very common in the area. Calcite is soft…a penknife will easily scratch it but for example won’t scratch quartz. Very weak acid will easily dissolve it…even vinegar at approximately 5% acetic acid…producing CO2 bubbles, a distinctive feature associated with calcite.

Calcite is a dominate gangue material that precipitates from hot silver vein solutions in the area, and that is why it is so closely associated with silver here. In other geological conditions calcite does not indicate the presence of silver because it can form by other means and does not necessarily have to be associated with magmas at all. You can do the usual field tests and these identify calcite. The geology literature about the area confirms this to be true. Hope that helps…

Jim.

That's what I was hoping for, Jim. In my area, calcite is present but in very small amounts, often as inclusions in basaltic vugs. I'm guessing you used the chemical (acetic acid) test and hardness tests for identification. Either would have been sufficient, I think. What you probably consider basic geology for your area is uncommon in other parts of TNet. Hoping others will benefit from the discussion is all.

 

[Jim Hemmingway]

Tuberale...yes I fully agree with you. Its not difficult to sometimes overlook that others are not familiar with our area's geology.

It is quite distinctive here with the widespread, countless chunks of calcite lying about on the surface in the mining camps. Also we have very little by way of metamorphism. The maximum metamorphic ranking we see in this area is a greyish fine-grained rock called "argillite"...an intermediate between shale and slate. That contrasts sharply with the schists commonly associated with gold producing areas.

Jim.

 

[strickman]

making the banner ,on the t-net homepage. A lot of the times - it can lead to an article in the magazine.Plus some serious bragging rites.Making the banner on the worlds largest treasure site would have perks.Possibly helping your writing career.

 

[bartholomewroberts]

I never thought of detecting for silver.. I live in the West Kootenays in B.C. the site of some of the greatest silver finds in Canuck history... Sandon, New Denver, Kaslo, Nelson... all within a short drive or close reach.

Our silver tends to be more of a galena composition though. The mines, obviously, have been well worked... but there just might be a few spills or nuggets [if I may use that term] that could be found.

I have not given this any thought yet.. Any hints as to what you have found to work the best?

Bartholomewroberts

 

[deepskyal]

Very informative post and like the pics with it. Looks like a real bear digging in the rock, even though it's loose rock. I'd surely give it a try if I had such a site nearby. Congratulations of some very nice specimens.

Al

 

[Tuberale]

A few more questions, Jim.

1) Have you not come across any ferrous-nickel targets? Do you search for such targets?

2) Have you ever done acetic acid liberation of native silver from calcite? I think the results of such liberation might be visually stimulating. Your comments on total silver content in rock sample suggest you have either already done such work ... or have spent some time doing specific gravities.

3) This is a fascinating area! Are you uncovering other noteworthy mineral specimens here?

 

[Jim Hemmingway]

Thanks very much everyone...I apologize for a late response...been sidetracked over the weekend.

Al... its been quite a long time since we've talked, a special thanks to you for taking a moment to post your kindly comments.

Bartholomewroberts...I think galena type ores could be much more difficult to detect even using all-metal modes. I have quite a number of galena samples, some half-dollar samples will respond out to a few inches, and others...especially character pieces... don't respond as well. Possibly the amount of silver mixed-in would improve ore detectability...thats a guess... as I have no experience detecting those ores.

Tuberale...your questions:

1) Have you not come across any ferrous-nickel targets? Do you search for such targets?

Any target that will respond to VLF all-metal motion mode or PI units gets my attention. The only nickel related mineral that I know responds very well to these units in these parts is a nickel arsenide called "niccolite" or possibly may be known as nickeline in other areas. It tarnishes quickly to the same color as a tarnished copper penny, is quite heavy and brittle. With weathering it oxidizes to a green mineral called "annabergite". See the photos below...

2) Have you ever done acetic acid liberation of native silver from calcite? I think the results of such liberation might be visually stimulating. Your comments on total silver content in rock sample suggest you have either already done such work ... or have spent some time doing specific gravities.

I have done both extensively for many years. Acetic acid is a mild method for removing calcite without damaging more fragile silver whereas a solution of muriatic acid...around here that is about 37% hydrochloric acid (HCl)...mixed at roughly one part to three parts water is the usual acid wash treatment when required to expose silver. Nowadays I rarely use it for more than removing a very thin layer of calcite.

3) This is a fascinating area! Are you uncovering other noteworthy mineral specimens here?

Yes...there are many other minerals in the area for collectors such as cobaltite and its oxidation mineral "erythrite, niccolite and annabergite as mentioned above, chalcopyrite is abundant, serpentine, various sulfides of silver including acanthite and various ruby silvers, pyrrhotite...a conductive iron sulfide, etc. The list goes on... but these are the ones that are found rather easily visually or otherwise respond to a metal detector.

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Thanks Tuberale for showing such an interest in this topic...

Jim.

 

[Tuberale]

Thanks for the great photos, Jim!

We have something called nickel bloom in Oregon too, but in quartz. Saw a gorgeous piece at the Herman Oliver Museum in Canyon City (near John Day) in 1977. Also called chrysoprase, a semi-precious stone. The piece I saw was particularly interesting as it was chrysoprase on approximately 1/2 of the stone, and the other half rotted quartz with vugs. Most vugs had gold nuggets in them, showing up nicely in cut and slabbed specimen. Certainly worth searching through the mineral specimen collection just for that one piece.

Nickel is rare in the U.S. Oregon has several places where nickel can be found. Chrysoprase is common on the ground on Little Canyon Mountain in Grant County; and the only nickel mine in the United States was located near Riddle in Southern Oregon. The mine and smelter shut down several years ago. And Josephenite from Josephine County can easily be mistaken for meteorite: one of the few naturally-occurring minerals that is similar.

 

[Jim Hemmingway]

Hi Tuberale...I wondered why you asked about ferrous-nickel targets. I immediately associated this question with meteorites. I doubt I would recognize a meteorite. And I hadn't known about Josephenite before you mentioned it. You seem very well informed about minerals, particularly in your area. Your mention of chrysoprase had me scurrying to my mineral books to do some reading.

The wonderful aspect of this hobby is that there is so much to know, and it never ends. Combine mineralogy with metal detecting = even more fun...

Jim.

 

[Tuberale]

Nice one!

In Oregon we don't have much silver. Seem to have higher proportion of gold (poor us!). During WWII, black sand deposits on the Oregon coast were being worked over ... again ... for gold. Miners were unhappy. The riffles in their sluice boxes would get clogged with silverish metal, and the gold would flow over the top and out of the sluice.

Seems some of the black sand deposits have small but appreciable quantities of platinum, palladium, osmium, iridium, etc. In the '30's, platinum was only worth $20-30/ounce. Times change.

 

[I Dig Relics Hoss]

Very Nice Hunks of Calcite and Silver!

 

[AGBlex]

that is an amazing find. are there any you're surely going to keep?

 

[kieser sousa/rip]

Pretty cool stuff...Thanks for sharing !

 

[baspinall]

Jim this one of the most informative posts I have read to date on TNET. So glad you decided to write it up. Those are amazing pieces. Now that would be a real treasure hunt in my book! Thanks.

Brian

 

[Captaindoodle]

Very nice finds. Amazing photos.

HH,
CD

 

[gleaner1]

Excellent banner smashing work right there.

 

[Jim Hemmingway]

Thanks to everyone for taking a moment to post comments here. Frankly I'm quite surprised at the response. Normally I restrict my posts to the Metal Detecting for Gold (gold prospecting forum) sub-forum and did so there providing a link to this location. That site has only seen 400+ viewers. I wonder how everyone found this site? It occurs to me that possibly I should be posting silver hunting articles at a different location.

In answer to the question above, I intend to retain all silver displayed here in my private collection. I pursue this hobby for the sake of outdoor enjoyment, the camping, and a natural love for both mineralogy and metal detecting. I have never sold any silver ore.

Lets post another photo of a small piece that represents the majority of silver found this past autumn. The photo does the specimen justice...what you see is pretty much how the rock appears on every side...Jim.

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[MKnTenn]

Incredibly beautiful silver. HH

 

[strickman]

CONGRATS ON THE BANNER Keep it up Jim ,Your post are the most informative on the web . Hope to see more of them . Truly amazing finds .Actually the find of a lifetime !!!!!!!