GB_Amateur

You may be onto something. Magnetism and electricity are close allies (look up Maxwell's Equations on Wikipedia) and even a static field is going to cause problems with a dynamically sensitive device -- like a metal detector. Modern coil housings have conductive inner coatings which have two purposes: minimize static buildup and shield the coil from from electromagnetic interference (EMI). If charge can build up between the outer surface of the coil housing and the inner surface of the protective cover one would expect problems. (Would be nice if Carl M. or Dave J. could elaborate, but they're busy building a new First Texas megadetector. )

I've been spoiled here by Steve's detailed and vast list of reviews of metal detectors used specifically for finding gold. Even though (from what I've read and seen) the use of a hand-held pinpointer is much less common among gold hunters than coin hunters, I'm wondering if anyone knows of a website the multiple reviews of those devices for any treasure hunting application. (Did see Steve's Garrett Carrot review in Gold Prospector mag several months ago.) There are quite a few to choose from, most in a common price ballpark (+/-) and it would be nice to see the features listed in a common format.

Would this happen to be the one about searching for the Lost Dutchman Mine? (Maybe I shouldn't ask, since you could have told us more about the show in your post -- I accept and respect that you have your reasons.) I've watched most if not all of these treasure shows. The biggest problem I have is trying to figure out what is real and what is planted/fabricated. The good news is that when you use non-professional subjects (i.e. untrained actors) it's less likely they'll be able to fake you out. The second biggest problem is putting up with all the drama/conflict b.s. Some shows are (far) worse at this than others. Third issue is all the voodoo/supernatural/pseudo-science crap. That is easier for me to ignore, and I guess it brings in audience (=advertiser $) so if that (and a bit of drama) is what it takes to get something decent on the air, I'll put up with it. Anyway, I was disappointed the Lost Dutchman show didn't have a second season. Still not sure about the veracity of all they showed (Jesuit connections, etc.) but the leader of the search team was likeable, seemed knowledgeable, and half his group appeared to know what they were doing. The other half....

It's about time someone spelled it out here. Television is a for-profit enterprise. Have you guys ever watched (or even flipped through) what is out there on cable? Ask yourself "why do they put this crap on?" The answer is pretty simple (and unfortunate/sad) "because that is what the TV audience wants to see." We have several channels whose names (and initial intent) is to educate: History Channel, Animal Planet, Discovery Channel, and National Geographic Channel. (All of them have treasure/gold shows, BTW.) Yet all of them have a plethora of garbage. History has the extraterrestrial alien believers every Friday night, Animal Planet puts on shows about sea monsters and Sasquatch which try to fool you into thinking are real (and 'fool' is a nice word -- they effectively lie to you in some cases). Discovery has "Naked and Afraid". I can't think off hand of what Nat Geo has that is misleading/phony, but I'm sure not interested in all their drug trafficking stuff. Are you? Having said that, what choice do we have? IMO, these are the best channels on mainstream pay cable when it comes to adventure, nature, science, and technology! Remember when 'TLC' meant "The Learning Channel"? A&E was really about (less than brain-dead) Arts and Entertainment? Have you checked them out lately? (Do so on an empty stomach because you'll have one afterwards either way.) Fact is that the four mentioned also have some decent shows -- you just have to filter through a lot of garbage. At the same time you need to watch ANYTHING on TV or the internet (including this site ) with a grain of salt. Anyone with an opinion (and that's everyone) and a keyboard can claim things as if they are based upon decades of scientific evidence, regardless if they were just made up. And TV isn't far behind that. If it sells then the veracity is secondary/unnecessary. But this doesn't stop me from watching, just watching selectively, and with a skeptical eye.

Next time I hear a sight is "hunted out" I'm going to remember this. Thanks for sharing your excitement and reminding us that it's still worth the effort.

This is way cool, for multiple reasons. 1) under the "everything isn't known" category, here are two long ago recognized and studied metals being alloyed to make something completely previously unknown. 2) when one is asked "why is gold so valuable?", even though its inert (non-reactive) qualities have long been recognized and appreciated, the reality is that its rarity (rarest element on earth with a non-radioactive isotope), artistic value, and effectively monetary 'aura' (look up the origin of that word!) are the real reasons. But tulip bulbs come to mind.... 3) although this article emphasizes the medical application, and for good reason, what is to keep this from being a contributor to other metallurgic applications? Titanium is a space age metal because of its low density and high strength/weight ratio. Making it even stronger... Let your imagination take it from there. Bottom line: any new industrial use for gold is going to increase its value. Fire up those detectors.

I can confirm that. "Can slaw" (pieces of aluminum cans that have been shredded by lawn mowers) give strong signals. Typically this is in the 60 --> 70 ID range on the GB Pro's discrimination scale. But aluminum foil can envelop a wider range, since the conductivity can be low (for small pieces) and high for large chunks, especially flat chunks. Gum wrappers, cigarette packs, and thicker foil used in grilling food can cover the spectrum from low 50's into even the 80's in my experience. And large pieces of aluminum cans are very conductive, also. Thanks for the tip. I'm going to put the 11 inch DD on this weekend and see if I can go deeper. I'm gaining confidence that the sites I'm searching are virgin (i.e. not recently searched by detectors) so deep is where the old coins are likely to be. That's the treasure I seek.

Well, I'm far from an expert, but I also use the Gold Bug Pro with the 5 inch coil. You probably are aware that US 5c pieces ("nickels") hit in the high 50's, typically 57 or 58. The old "ring + beaver tail" pulltabs also hit here, but since those went out in 1975 you shouldn't get too many, unless it's a park that hasn't been searched in which case it's worth digging them, IMO. Also, I mentioned in another thread that I found an Indian Head Penny last Saturday and it showed ~74 on the ID, right about where you often find the dreaded zinc pennies! One thing I've been speculating recently is that corrosion/deterioration affects the ID of US pennies of all types. Yes, a clean copper should hit at 82, but how about one that's been sitting in the ground a long time? I don't know. I have books and web articles that claim that Indian heads hit at four different ID's on some White's IB's and Minelab X-terras. But there were only two different composition Indian Heads: 1859-64 cupro-nickel and 1864-1909 95% copper, 5% (zinc + tin). So how do you get four ID's with that? My current theory: corrosion. As far as the spread on ID's, in my limited experience you can see this with coins that don't sit horizontally. Ideally a coin sits horizontally and you get a clean eddy current and tight ID, but get them off horizontal (especially vertical) and the variation is larger. How large? I'm not sure. Also I wonder about near neighbor trash. But one thing that helps is to rotate your body (and detector) 90% and scan the target again. Things that are asymmetric (e.g. nails and modern pulltabs = "square tabs") will give significantly different readings depending upon the orientation of the sweep with respect to the orientation of the object. As far as jewelry, I can't help you there but there are many here who can. I wish you well in your hunts!

Yes, but success is few and far between. The last time I found a silver coin was a dime I got in change at a Northeast Illinois toll booth about 10 years ago. (Value almost paid the toll. ) Theft and younger people cleaning out deceased parents/grandparents nick-nack drawers are likely the only way they get there today, and they wont stay back in circulation very long. I recall finding a Wheatie within the last month, but not particularly old and of no numismatic value. Jefferson 5c gives one a better chance because you have to read the date (until recently) to tell the oldest (first minted in 1938) from the new ones, unlike Wheaties where any nincompoop can cull out the older ones (pre-1959) by looking at the reverse. Saturday while MD'ing I dug up a 1904 Indian Head (bad shape due to our caustic soils) and it brought back memories. I started coin collecting in 1959 and never found an Indian Head, whether in change (my parents' back then) or going through bank rolls which I did quite a bit. So 50 years was enough time to clean out pretty much all of the Indian Heads. But you could find Buffalo nickels (last year 1938), Mercury dimes (1945), Standing Liberty quarters (1930) and Walking Liberty halves (1947) in the 60's, until the silver cleanout that left us with nothing but dull (in more ways than one) clad by about 1970. Thus 20-30 years and you still have (or had...) plenty of the previous designs in circulation but by 50 years they are gone. Wheaties more/less confirm this (58 years now). Believe it or not (I can't, or won't), we've had those p-o-s zinc pennies for 35 years now. "Those were the days, my friends. We wished they'd never end...."

Why steel?

Here are a couple such devices: https://www.bostonscientific.com/content/dam/Manuals/us/current-rev-en/91005926-01RevC_Precision_Novi_IPG_DFU_en-US_S.pdf https://www.bostonscientific.com/content/dam/Manuals/us/current-rev-en/91057051-01RevA_Precision_Spectra_IPG_DFU_en-US_S.pdf It appears they can be tuned to pulse between 2 per second and 1200 per second, which overlaps the pulse rate of at least some PI detectors. There could be other manufacturers than just Boston Scientific. It appears that they can be turned on and off although I don't think that is typically a patient option but rather done by a tech/med-pro in an office. It still would be worth asking about. I wonder if they could allow you to test this -- e.g. with a unit that has yet to be implanted but can be operated, or even with a volunteer who already has one. You supply the detector and expertise on that end! Keep in mind "a little knowledge is a dangerous thing" and that especially applies to searching the internet, which is what I've done. Hope you find a compatible solution. My wife suffers from spinal cord induced pain and from listening to her experience it is no fun.

Thanks, Steve. I reviewed the Minelab webpage for the 505 and unfortunately they don't mention this. Similarly when they let you compare multiple models side-by-side (e.g. 505 vs. 705) they also fail to point this out. In both cases they state "All Metal" modes. By contrast, in the Garrett catalog when comparing the Pro vs. the Gold models, Garrett does an excellent job making the point that the Gold has "True All-Metal Mode" as opposed to the Pro which it notes does not.

Minelab's site/advertising lists the 505 applications as "coin, relic, jewelry and beach". For the 705 it adds "gold prospecting". But when you look over the details and specs for the two instruments, it's hard (for me) to see the distinction. Both have all metal mode as well as discriminate mode. Both operate at 3 kHz, 7.5 kHz, and 18.75 kHz (all determined by the coil you choose to attach). Both have manual ground balancing (705 also has automatic and tracking in addition). Both have adjustable threshold and adjustable sensitivity. Both have fine-tunable frequency to eliminate EMI. The Minelab site list something called "detect modes" where the 505 says (1) "Coin and Treasure" while the 705 lists (2), that plus "Prospecting". Are these preprogrammed setup options? For some of the adjustable settings the 705 has higher precision than the 505. An example is the Ground Balance where the 505 says "0 to 50" and the 705 "1 to 90". Sensitivity is another example: 1 to 20 vs. 1 to 30. Pinpointing is more detailed on the 705, and the 505 doesn't have backlighting. Discrimination divisions can be configured to a higher level (iron mask on the 705 and more segments). So, yes, the 705 does have more detailed features. But what distinguishes the 705 as a prospecting detector compared to the 505 (for which the Minelab site's implication is that the 505 isn't a prospecting detector). And if one were to compare the 505 to competition from Garrett (AT Gold) and Fisher (Gold Bug family) to name just two, what makes those prospecting detectors and leaves the 505 in the "coin and treasure" (only) category? BTW, I did read Randy Horton's "Understanding your x-terra" monograph and he does talk about the prospecting mode of the 705, but it's not clear that one couldn't configure the 505 to be close to these settings.

Although pure antimony has a density that is too low, this could be antimony allowed with something heavier. Also, bismuth is a chemical relative of antimony but with higher density. So if appearance is associated with chemical properties then maybe this is a bismuth alloy. I have looked for those and can't find one that matches, though. I'm running out of properties I can think of and have the ability to measure: streak is dark gray; Moh's hardness is ~6 (scratches soda lime glass but is scratched by tool steel). Oh, and the Gold Bug Pro's Fe3O4 gives a high reading, and the closer the coil gets to this unknown sample the higher it gets. That's true in both all-metal and discriminate mode, and seems to be higher response on this scale in discriminate. I don't really understand completely what this means. Given that the sample isn't magnetic it can't be magnetite. So what is this meter reading value really telling me? Finally, I did a resistance measurement using an ohmmeter with curious results. On the lustrous face the resistance was nearly non-existent (less than 1 ohm) and on the flat black face the resistance was imperceptible -- greater than 20 Megohm. I don't think resistance is a particularly useful quantity when it comes to ID'ing rocks/minerals but very low resistance has to be rare. Of the minerals I listed earlier which are in the spec. gr. ballpark (and the measured hardness), ferroselite is intriguing. That is FeSe2, a chemical compound of iron and selenium. It is found in both Colorado and Utah. Nothing is perfect and the images I find on the web appear to show a higher granularity, but otherwise look pretty close. I'm wondering if we are getting close to saturation as far as identifying this specimen here. There are other analysis options (like x-ray fluorescence) but are they worth it? Bottom line is I have a dense ore sample which gives very high metallic readings on both a 19 kHz VLF detector and a 10 microsecond delay PI detector. If I ever run across this in the wild I'll be in better position to draw conclusions, even if those conclusions aren't as sound as I'd like.

Nope, not magnetic, but I agree it does look similar to some photos of samples of magnetite I've seen. My biggest concern lately is that I got the volume wrong, but just measured by a different (related) technique and got the same result: 10.3 cm^3. So spec. gr. really is 7.2 (actually 7.21 to higher significant figures; assume an uncertainty of a few hundredths). Here's a good reference for mineral density (specific gravity), in order. About 1400 names in this list: http://rruff.info/doclib/cm/vol6/CM6_273.pdf Here listed between 7.10 and 7.30 are the following: Rammelsbergite, Huttonite, Georgiadesite, Wittite, Pararammelsbergite, Matlockite, Huebnerite, Ecdemite, Calomel, Trogtalite, Cohenite, Safflorite, Acanthite, Argentite, Domeykite, Ferroselite, Hastite, Mendipite, Mimetite, Curite, Finnemanite, Wolframite, Empressite, Tetradymite. (Ancanthite, Argentite, and Wolframite ought to sound familiar.) So far looking up those on this list, I haven't found a good match. But I'm not finished. Some of these are apparently rare. I guess my next concern is that what I have is a rock (so mixture of minerals), not simply a mineral.

OK, here goes -- first time uploading photos and I'm not much of a photographer. Two photos with tape measure in them are taken with flash. Other one was taken in natural (scattered) sunlight. A couple more pieces of evidence: 1) strong rare-earth magnet did not attract. 2) Fisher Gold Bug Pro gave strong response and (surprising to me) a steady discriminator reading of 60 +/- 1 at any orientation. US 5-cent piece "nickel" reads high 50's and zinc penny low-mid 70's. Typically something that gives a reading here is aluminum but I recall some gun shell casings (brass?) being in the 60's as well.

Well, bad news (or maybe not) -- the sample I measured that got a strong response on the the White's TDI isn't bornite. Laying in bed last night I started to suspect the density was wrong. Its mass is about 75 g and for a specific gravity of 5 (bornite is between 5.0 and 5.1) that would mean its volume is 15 ml (or cm^3) and it didn't seem that big. I measured the volume today (by water displacement method) and got 10.3 ml! So its density is 7.2 g/ml which is way too high to be bornite. (More on what it might be shortly.) I then turned the detector back on and tested three other pieces which look very much like the picture Steve posted above, and they gave no noticeable response with the TDI. (I'm assuming Steve meant bornite sounds off with an IB/VLF detector. Presumably the delay of 10 microseconds on my TDI/SPP is long enough to miss detecting the reflected pulse.) So, what ore do I have that gave such a strong response with the TDI? 7.2 is getting up there, and I don't think there are many minerals with spec. gr. at or near this value. One obvious and common one is galena (PbS = lead sulfide) but my sample doesn't look like any pictures of galena I can find on the web. It isn't lustrous and doesn't have the usual flat crystal faces that galena (always?) shows. It is dark (brown/black), and amorphous looking (no obvious crystal structure to my untrained eye). There is some sign of gold-lustre which reminds me of pyrite but that is only on less than 10% of the surface -- not representative of the majority. If it doesn't contain lead, tungsten is another very dense metal (not far from gold in this property, actually) but again, I can't find any photos on the web of tungsten ores that look like my specimen. I remember the booth I bought this in -- picked up three total pieces at about $1 each. (I bought another peacock ore sample from another dealer, too.) I asked the woman who sold me it as Peacock Ore what the chemical composition and/or accepted mineral name was. She asked her son and he shrugged. Bottom line is that I was looking for ores to test with my detector and I sure got one (for cheap!), but unfortunately I don't know what it is. I'm still going to test the response on my Fisher Gold Bug Pro (along with a zillion other rocks) and I should be able to get a good digital ID from the discriminator circuit but I doubt that will help me much in figuring out what it is.

On rereading my own post I realize that was both inaccurate and insensitive. There are quite a few people who stand to gain from higher gold prices, such as metal detector dealers and metal detecting and gold panning tour guides and camps. Even authors can get a big influx of book buyers when increasing gold prices are in the news. I don't know the stats for this site, but in my experience, for every poster there can be several silent members and guests. It seems many posters fit into the recreational miner / supplemental income group as contrasted to those who make a living from mining, but it wouldn't surprise me if pros monitor the site. For them, the difference between $1400/tr.oz and $1000/tr.oz can be the difference between working and collecting unemployment.

Went to the local gem and mineral show a couple weeks ago and picked up some nice ore samples. One of the items going cheap was peacock ore, which Wikipedia says is the common name for the mineral bornite. According to them it has a specific gravity of ~5 and a chemical composition of Cu(5)Fe(1)S(4). My White's TDI PI detects a 74g sample at 10 inches in air. That's one hot rock! I suppose this could be a real payoff for copper if found in quantity. But for gold nugget hunters it's got to be a sting no matter where it jabs. Anyone found this while out hunting?

Am I missing something, or is no one looking at the commodity futures market for gold. No, they aren't right all the time, but most of the traders there have only one or two things to be concerned with, and it's their sole livelihood. For most of us (yeh, not all), we can live with $400/tr-oz gold or $2000/tr-oz gold and not be concerned about what's paying for the next meal. I hope it's going up, too, but there are more things in life than hope. Fun thing to speculate on, anyway.

First off, I'm talking about placer gold. Secondly, I realize this is a simple question with a very complicated answer. But in probability/statistics/percentage terms, I think it's not that crazy. Most, if not all gold is going to end up in the ocean if it's not recovered by one of us. But even once loose from it's origin that could take many 10's of millions of years. In the meantime, gravity is pulling it towards the earth's center. Even dense clay can stop it for a while, but usually it sinks until it reaches bedrock, and even then it can be horizontally displaced unless it falls in a crack/crevice. If you're using a metal detector there is a minimum size that can be detected. "Young gold" (that which has only reached its current location in the last days, months, or even few years) tends to be sub-threshold gold in terms of metal detecting (I think -- please correct me if I'm wrong). So if you're going to find placer gold with a metal detector it most likely has been at or near its current location for a long time, meaning on the order of tens or hundreds of thousand of years at a minimum. (Obviously there are exceptions, but I'm talking in general.) So, to cut to the chase, if I'm using a metal detector to find placer gold and I'm not getting to bedrock, am I just spinning my wheels? Postscript: I'm no expert on this. Maybe my assumptions and conclusions are completely bogus. If so, I welcome/encourage you to say so. I'm trying to learn, not protect my ego.

I'm curious as to why you state this in past tense "...could have made a real impact..." Do you think the opportunity is gone? AFAIK the White's TDI/SL is easily the lightest dry land PI detector on the market today, even though it's been around several years. It seems to me that there is still a place for a lightweight, affordable PI detector with greater sensitivity than the TDI's, and from what you indicate the ATX has the electronics to be just that if it could go on a diet and get rid of the military tank style structure.

Please keep us informed as to the performance of that coil, Rick. I still don't get it. Glad Steve responded but his reply seemed matter-of-fact. I guess one must give up something to get this quiet (ignoring hot rock) performance, and the obvious concession is insensitivity to small gold. But I don't like assuming so I hope someone with 'data' can go into this deeper. That thread you posted seems pretty lean, unless I didn't read it correctly. There are used Omegas and Gammas on Ebay periodically (including now) for reasonable and even better discounts to new prices. I bought a Gamma this past December for $200 and gave it away as a Christmas present. Maybe I should try to get it back!

These archive records provide a lot of value to historians of all kinds, including metal detectorists and gold seekers. Although I'm far from an expert on vehicle design I have to take exception to this poster's date of 1931. I don't think there were any cars in existence that early that look like those in this video. Off at least 5 years and maybe as much as 10. She was trying to tie this video to a bridge opening which is a good attempt, but it takes more than that to tie down a date. The newest thing you can find provides a lower limit on age. I.e. if you find a 1951 Wheatie you can say for sure it wasn't dropped before 1951, but the upper limit is impossible to determine with certainty. Maybe someone stole grannie's coin collection yesterday and this slipped out of the grasp in his attempt to escape undetected. Sure wish I was out there with you and could find the spot of this town and swing my detector on that baseball diamond! If not paved over it should still hold a horde of prewar keepers. Oh, to dream but much better to do....

Ok, am I the only (other) person surprised that the Teknetics Omega (IB unit operating at 7.8 kHz) with its stock elliptical concentric ignores hot rocks? Which is it, the frequency, the coil type, or both? 'Cause my (cousin) 19 kHz Fisher Gold Bug Pro with both 5 inch round DD and 5in x 10in elliptical DD loves to sing when it sees those babies (Arizona and Colorado -- 2 for 2).