One ounce silver rounds.

Purchased in Richmond, CA early 1990s for use in castings. Dan Lewis, a coin dealer, tells me that these are called "silver rounds" because they are round but are not actually coins issued by any government. He reports they are the part of the numismatic world known as exonumia.



I've cast a dozen or so little things out of silver over the years. It's not as expensive as you might think. See zinc for a long story about metal casting.



Source: Coin Shop in California

Contributor: Theodore Gray

Acquired: 15 April, 2002

Price: $5/ounce

Size: 1.5"

Purity: 99.9%

Sample Group: Coins

Turnings, 99.998%.

Kindly donated by David Franco, who sent many elements after seeing the slashdot discussion, and this one after I sent him some Mathematica t-shirts. My coins are bigger, but his turnings are more pure.

Source: David Franco

Contributor: David Franco

Acquired: 11 June, 2002

Price: Donated

Size: 0.2"

Purity: 99.998%

Sassanian Dirham of Chosroes II.

This certainly takes the prize for oldest sample: 1400 years. [But see the tetradrachm below for an even older sample added a few years later.] Dan Lewis, a coin dealer (click on source link below for contact information), sent it for free (!) because it's broken and he thought it would make a good silver sample, which it certainly does. It's quite brittle, which indicates it's not terribly pure. In fact, analysis by x-ray fluorescence spectroscopy at the Center for Microanalysis of Materials, University of Illinois (partially supported by the U.S. Department of Energy under grant DEFG02-91-ER45439) indicates that it's 93.5% silver, 6.5% copper, but let's see you do any better 1400 years ago!



I asked Dan how much he though this coin would have been worth when it was minted. He said he could only guess that because of its size and silver content it was probably fairly valuable, certainly more than a week's wages. So maybe someone bought a horse with it one time, or used a handful to buy a Roman as a slave. Given how long it was probably in circulation, it's no doubt been used to buy a lot of things by a lot of people. History is funny that way, especially when you're holding it in your hand.



Dan sent the following interesting history of this type of coin:

From Ardashir I in 211 A.D. to Yazdegerd III (632-651 A.D.) a series of 42 Sassanian kings ruled over Persia. The Sassanians were ardent devotees of the Zoroastrian doctrine. This fire cult was vigorously disseminated throughout the empire.



In the early period they were the most persistent and successful foe of the Romans. In 260 A.D. the Roman emperor Valerian, while marching through Mesopotamia, was captured and spent the rest of his life as a captive. A century later, in 363 A.D. the Roman emperor Julian II (The Apostate) died from wounds suffered fighting the Sassanians in their capital city of Ctesiphon, near Baghdad. His successor, Jovian, found his situation so perilous that he could only extricate himself and his army by a humiliating peace which ceded many possessions along the Tigres, the great fortress at Nisibis and a Roman pledge to abandon Armenia.



One of the last Sassanian kings, Chosroes II (590-628 A.D.) appears on the obverse of this coin. When his friend and ally the Byzantine Emperor Maurice was assassinated in 602, Chosroes II embarked on an initially successful, protracted campaign of revenge against the Romans. In 614 he invaded and sacked Jerusalem and carried off the remains of the Holy Cross to Ctesiphon. Chosroes fortunes changed when the Byzantine Emperor Heraclius retook lost territories from the Persians and finally in 627 returned the Cross to Jerusalem. This event was well received by Christians who celebrate the event at the annual feast of the Exaltation of the Cross.



Chosroes weakness led to the defeat of the Persians by the Byzantines. During the ensuing revolution Chosroes was deposed and murdered by his son Kavadh II in 628. One hundred years of nearly constant war with the Byzantines and Chosroes incompetence left the Sassanian Empire crippled and vulnerable to their demise at the hands of the emerging Islamic Arabs.



This coin is an example of late 6th and early 7th century Persian craftsmanship during the zenith of the Sassanian Empire. That empire emerged over a ten year period beginning in circa 224 A.D. when King Ardashir I expanded his local fiefdom in Iran to include all of Iran, Iraq, Afghanistan, and much of the remainder of central Asia. He introduced a new coinage with his own crowned portrait on the obverse, his throne and a Zoroastrian fire altar on the reverse and inscriptions in the Pahlavi language. Although the portraits and styles would change with each succeeding reign, the basic design would remain for 450 years. The most significant image change was made by Ardashir's son, Shapur I (241-270 A.D.) when the throne was eliminated and the altar was flanked by two holy figures. Later, mintmarks and regnal dates would appear. Some of the royal crowns that are pictured were reputed to be so heavy with gold and jewels that the wearer had to have them suspended from the ceiling above the throne by chains in order to wear them.



Source: Dan Lewis

Contributor: Dan Lewis

Acquired: 18 June, 2002

Text Updated: 19 February, 2006

Price: Donated

Size: 1"

Purity: 93.5%

Sample Group: Coins

Cool snake bracelet.

I bought this bracelet in a flea market in London some time in the early 1980's, when I was there near the end of high school I believe. I don't have to tell you how incredibly cool I looked with it on, do I?

Source: Flea Market in London

Contributor: Theodore Gray

Acquired: 10 January, 2003

Price: $10

Size: 3"

Purity: >90%

Non-crystalline powder.

This is silver that feels too light to be silver. It's a very unusual type of powder, light and almost fluffy, Greg is kindly helping me flesh out some elements with different and unusual forms, like wires, meshes, wools, foils, etc: This non-crystalline powder is probably the most peculiar thing he's sent. He also sells lots of other unusual elements on eBay: Check the source link for more information.

Source: Greg P

Contributor: Greg P

Acquired: 18 April, 2003

Price: Donated

Size: 1"

Purity: 99.99%

Sample Group: Powders

Wool.

What do elves scrub their pots with? Probably silver wool like this. Finer than the finest steel wool and definitely much classier, this wool is made of high-purity silver. Greg is helping me flesh out some elements with different and unusual forms, like wires, meshes, wools, foils, etc. He also sells lots of other unusual elements on eBay: Check the source link for more information.

Source: Greg P

Contributor: Greg P

Acquired: 18 April, 2003

Price: Donated

Size: 1"

Purity: 99.99%

Shiny crystals in pretty mini-flask.

This is a small (1/2" diameter) round mini-flask containing some very, very shiny silver crystals formed by slow electrodeposition. The flask is closed with a cork, which probably won't exclude oxygen well enough to completely prevent tarnishing, but we'll see. I'm going to seal the other similar silver crystals from the same source (see next sample) under argon and compare the rate of tarnishing.

Source: Attard's Minerals

Contributor: Warut Roonguthai

Acquired: 5 May, 2003

Price: Donated

Size: 1"

Purity: 99.999%

Mini periodic table table for Popular Science.

In early 2003 I got an email from an editor at Popular Science column asking if I'd like to write a monthly column. Of course I said yes, and the second article (in the August, 2003 issue) is a story about lost wax casting as I did it when I was fifteen or so. For the photographs in the article I made a few little periodic table tables out of various metals: This one is made of silver (about $50 worth), and I also made ones out of copper, zinc, and bismuth.

Source: Coin Shop in California

Contributor: Theodore Gray

Acquired: 30 May, 2003

Price: $5/ounce for silver rounds

Size: 3"

Purity: 99.9%

Chinese Sycee coin.

This is, almost certainly, a fake. For about a thousand years ending in the early 20th century, stamped silver ingots like this were used as currency: I'm told one like this would have fed a family for a month. But in the 1930s there was a mandatory melting down program to turn all the old currency into new currency, so very few genuine Sycee coins remain, and they are valuable antiques.



Because they are valuable, they are often counterfeited, sometimes in quite sophisticated and difficult to detect ways. For example, a latex mold can be made of a real one, and castings made from that mold, in real silver. These can be very difficult to distinguish from the genuine article.



In this case, however, I paid less than 1/5 of the melt-down value of this coin, which weighs about 1300 grams. It's pretty unlikely that anyone would sell something actually made of silver for less than the value of the silver. So it's almost certainly not silver and therefore not genuine.



The interesting question is whether it's a new forgery or an old one. Turns out fake ones were made in great numbers while these coins were in circulation, and the government did not destroy those, only the real ones. So there are a large number of old fakes being sold. Of course, being old and with a story, the fakes are now valuable antiques too, if they are in fact old. (New fakes won't be valuable for another hundred years or so.)



I have no idea whether this is a new or an old fake. It looked old before I cleaned it (of course, I only cleaned it after I was pretty sure it wasn't real, because polishing a genuine silver Sycee would probably not be a good idea from a historical preservation point of view). I will, however, soon know whether it's got real silver in it: I'll have it tested as soon as I have a free afternoon.



In the mean time, here are some interesting sites about this type of coin:

http://www.sycee-on-line.com

http://www.sycee.net



And in case you can read Chinese, here is the inscription from the bottom and the characters drawn cleanly by my colleague Xin Kai from Singapore:





Source: eBay seller chinaembroidery

Contributor: Theodore Gray

Acquired: 3 June, 2003

Text Updated: 29 January, 2009

Price: $19

Size: 3"

Purity: 0%

Sample Group: Coins

Silver leaf.

I think it's pretty remarkable that you can buy sub-micron thick films of several different pure metals: Click the Sample Group link below to see all the ones I have, which represent pretty much the complete list of those that are commercially available. (Many, many different mixed alloys are also available in leaf form.)



Silver leaf is relatively inexpensive, but it tarnishes and can't be used outdoors at all. For this reason, palladium leaf is often used as a sort of imitation silver, which is amusing since palladium costs between 50 and 100 times as much as silver depending on the current market.



Leaf like this is so thin it has to be picked up with special Red Squirrel hair brushes (none of that Gray Squirrel crap, mind you) and when it wafts down onto an object it conforms to the shape of the surface, settling in even to details as fine as a fingerprint.



I bought this leaf from a store in New York when I was visiting there with my six-year-old daughter Addie: You can read about our visit here.

Source: New York Central Art Supply

Contributor: Theodore Gray

Acquired: 11 July, 2003

Price: $10/25 sheets

Size: 3.5"

Purity: >99%

Sample Group: Metal leaf

Chinese coin.

I got these coins in a gift shop in San Francisco's Chinatown district. I don't know if they are genuine Chinese coins, or if they are genuine silver, but at least they didn't cost less than their melt value, which is usually a pretty good sign of a fake silver coin! I'll test them by XRF when I get a chance. I have to say I'm not entirely clear why a Chinese coin would have English writing on it, but they are quite pretty.

Source: Gift Shop in Chinatown

Contributor: Theodore Gray

Acquired: 24 June, 2003

Text Updated: 29 January, 2009

Price: $6

Size: 1"

Purity: >95%

Sample Group: Coins

Bullion bars.

These are an assorted lot of simple one-ounce silver bullion bars from a local coin shop. They are sold for not much more than the current spot price of silver, which is good because I buy them to melt down into things like the chain link below. These four I've kept as samples for the table, they will be spared the melting crucible.

Source: Golden Nugget Coins

Contributor: Theodore Gray

Acquired: 7 August, 2003

Price: $6/ounce

Size: 1"

Purity: 99.9%

Link in multi-metal chain.

I had been wondering about how hard it would be to make a multi-part graphite mold with which I could cast chain links around each other. That is, given an existing link, cast a new one interlinked with it. This turns out to be quite do-able: Here is the mold I made (using my drill press as a vertical mill and a round-ended router bit):



In case you ever want to try this, I'll give you an important hint: The third link is the real test, not the second one.



Using this mold I have cast a chain out of all the metals I can easily cast. Click the Sample Group link below to see all the links together.



This chain (counted as one sample) is the 600th sample added to my collection.



Source: Golden Nugget Coins

Contributor: Theodore Gray

Acquired: 9 August, 2003

Text Updated: 20 February, 2006

Price: $1/pound

Size: 3"

Purity: 99.9%

Sample Group: Multi-metal Chain

10 ounce bar.

This is a large 10-ounce ingot of silver: I bought 8 of these, one for me, three for Max Whitby, and the rest to make a 2" diameter silver ball for Oliver Sacks. Northwest Territorial Mint has the best price I could find for raw silver: Only 75 cents over the current COMEX price with a 50 ounce minimum (at least, that was their price in 2004).

Source: Northwest Territorial Mint

Contributor: Theodore Gray

Acquired: 15 September, 2004

Price: $72

Size: 3"

Purity: 99.9%

Idaho silver crystals.

From the eBay description: They are from Silver Capital Arts and silver crystals are produced at the Sunshine Mining Company Silver Refinery in Wallace, Idaho. The exquisite crystal-line silver is a unique formation of 99.95 percent silver. The pure quality of the crystal presents a brilliant example of the light-reflective properties of Silver. The Crystal structure was created by electrical deposition of Silver Ions, and each formation is unique in its structure.

Source: Northwest Territorial Mint

Contributor: eBay seller ldhappy55

Acquired: 16 September, 2004

Price: $2

Size: 1.5"

Purity: 99.9%

Silver lining shorts.

These boxer shorts are made of silver-coated thread, and are meant to protect you from electromagnetic fields (EMF). Whether you need protection from electromagnetic fields is beyond the scope of this item description: Suffice it to say that enough people think they do that there is money to be made selling them expensive underwear.

Source: LessEMF

Contributor: Theodore Gray

Acquired: 20 June, 2005

Text Updated: 11 March, 2007

Price: $64

Size: 15"

Purity: <5%

Sample Group: Medical

Shielded cap.

A certain brand of disturbed individual can be observed wearing a tinfoil hat to protect their brain from imagined mind rays being used by aliens, or the government, or an alien government, or something, to control their thoughts. I'm sure the makers would be terribly insulted to hear me say it, but let's face it: This is a tinfoil hat. OK, it's actually made with a "sophisticated NaturaShield fabric woven from cotton with an ultrathin Silver/Copper core thread for excellent radiation protection", and it's supposed to be used to protect you from powerline EMF, which some people believe is harmful, or cell phone radiation, which slightly more people believe is harmful. But when you get right down to it, it's still a tinfoil hat.

Source: LessEMF

Contributor: Theodore Gray

Acquired: 20 June, 2005

Text Updated: 11 March, 2007

Price: $30

Size: 15"

Purity: <5%

Sample Group: Medical

Tetradrachm.

This coin dates from 261BC, which makes it my new oldest sample: 2,267 years old at the time it was added to the collection. I read somewhere that when the Euro was introduced in Greece, it was the first time in 3,000 years that a coin called the Drachm was not being minted somewhere in that ancient country. Seems like a shame somehow. It's hard to fathom how old something like this really is. When Christ was born it was already older than the United States is now. Do you suppose someone had it in their coin collection at the time?



The British Museum has a much nicer example of this coin from about 60 years earlier. Slight differences indicate that mine might be a version from a different region, or possibly a forgery, though if it is fake it's probably an ancient fake, which is just as interesting as an old real coin.



In any case, my primary reason for buying this (not cheap) coin was to use a photograph of it in a periodic table poster. Bizarrely, it's cheaper to buy a stunning 2,267 year old pure silver coin than it is to license a photograph of one, plus you get to keep the coin. Look at the rotatable image to see the other side of this very fine coin.



I chose this sample to represent its element in my Photographic Periodic Table Poster. The sample photograph includes text exactly as it appears in the poster, which you are encouraged to buy a copy of.





Source: Specialty Stamp & Coin

Contributor: Theodore Gray

Acquired: 13 February, 2006

Text Updated: 29 January, 2009

Price: $300

Size: 1"

Purity: >90%

Sample Group: Coins

Coin from 98-99BC.

This is a smallish coin that I thought was going to make a better photograph than the tetradrachm listed above. In fact it didn't, but it's still a very nice example of an ancient coin. Within a few weeks of posting this entry with a note that I didn't know much about the coin, reader Peter Marren helpfully supplied the following learned (and fascinating) analysis of the coin and why it was expensive. The coin is a denarius (silver penny) of Emperor Trajan, who reigned from AD 98 to 118. You can tell roughly when the coin was minted from the letters COS II on the reverse, meaning second consulship, which places it near the beginning of Trajan's rule. By contrast with many later coins, not to mention the warlike scenes on Trajan's Column in Rome, this coin has a nice peaceful message. The emperor is styled IMP.CAES.NERVAE. TRAIAN.AUG.GERM.P.M., that is Imperator Nerva Trajanus Caesar Augustus Germanicus Pontifex Maximus (there being no J in Latin). On some later coins he is also styled OPTIMUS PRINCEPS or 'best ruler' (literally 'best first man'). This seems to have been no empty honor. Trajan had a colossal reputation in his own lifetime and was remembered afterwards as the model of everything a Roman emperor should be. 'May you be as wise as Augustus and as successful as Trajan' was the saying. Even the Christians admired him. Dante reworked an old tradition that Trajan was secretly baptized on his deathbed by placing him in Paradise while other pagans, good or bad, were stuck in Hell. That chunky coin portrait of him is instantly recognizable, and compares well with Trajan's portrait busts. He was the last clean-shaven emperor for a long time.



Anyway, the reverse of the coin shows the Goddess Vesta seated facing left and holding out a patera or offering dish. Vesta was the deity of hearth and home, of family life. Suitably, the inscription emphasizes the emperor's title of Pontifex Maximus or chief priest, and also his role as tribune (Tribunicia Potestas - tribunicial power), that is, as the people's representative . The full inscription reads PONT.MAX.TR.POT.COS. II. Or Pontifex Maximus Tribunicia Potestas Consul II . Vesta looks a bit like Britannia on the old English pennies, and probably conveyed the same sort of reassuring message. She looked after both the emperor's family and the extended family of the Roman Empire in which people then identified to an extent we modern Europeans can scarcely empathize with now. So its a nice little piece of history from the pinnacle of Roman pride and confidence. It should weigh roughly 2.9 grams.



That's why this coin cost you a hundred bucks. As a general rule coins of the successful emperors are scarcer than the unsuccessful ones. In times of uncertainty coins were buried, maybe their owner was killed and the coins left to be dug up by archaeologists armed with metal detectors nearly two thousand years later. Trajan's coins on the other hand were traded, spent and eventually melted down. That's why you can find coins of forgotten emperors like Maximinus or Gallus for the price of a bus ticket, but have to pay serious money for one of Julius Caesar or Augustus.



Where did the silver come from? An expert could probably identify the mint, but I think the biggest Roman silver mines were in what is now Spain. A lot of them were worked out in ancient times, and you can still detect the atmospheric metal pollution in two-thousand year-old ice deep in the Greenland ice-cap. But its just possible that your coin might have come from silver mines in Cornwall here in dear old Britannia. By the by, I think 95 percent silver is a bit optimistic. If you analyzed it I suspect you'd find a lot of copper. I have lowered my estimate to 90% based on Peter's skepticism.

Source: Specialty Stamp & Coin

Contributor: Theodore Gray

Acquired: 13 February, 2006

Text Updated: 29 January, 2009

Price: $100

Size: 0.5"

Purity: >90%

Sample Group: Coins

Element coin.

Dave Hamric sells element samples under the name Metallium. He's developed a line of coins struck out of various common and uncommon metals: They are quite lovely, and very reasonably priced, considering the difficulty of creating some of them.

Here is the back side of this coin (click either picture to see it larger):



Click the Sample Group link below to see many other coins made of various elements, or click the link to his website above if you want to buy one like this.

Source: Dave Hamric

Contributor: Theodore Gray

Acquired: 1 December, 2006

Text Updated: 14 January, 2007

Price: $10

Size: 0.75"

Purity: >99%

Sample Group: Coins

Silver tracheostomy tube.

A tracheotomy is an operation in which a hole is made in the airway where is passes through the neck. The opening, which may be permanent or temporary, is called a tracheostomy. (There, now you know the difference between tracheotomy and tracheostomy: One is the operation, the other is the result. To further confuse things, the hole itself is also known as a stoma.)



If you have a tracheostomy you generally need some kind of a tube to keep it open and allow air to flow smoothly. This one is made of solid silver, for reasons that seem obscure to me. It's not unusual, many of them were made this way, and so far as I can tell they are still in use, or at least were until quite recently. Silver seems like an odd choice of metal for medical uses given that it tarnishes so easily. I can see it now: "Jeeves! Come here will you, I'd like you to polish the silver this morning, and don't forget to do my tube while you're at it."



Perhaps they started using silver just because it's an easy metal to work with, and there were many silversmiths available who could construct the requires shapes, but I'm just guessing here. I even found a report in the literature of a silver locket being attached to a silver tracheostomy tube for cosmetic reasons. These days silicone and other plastics seem to be more commonly used, which sounds like a good thing to me: Soft silicone sure must be much more comfortable than a metal tube.



Several readers have pointed out that silver has anti-microbial effects, and may have been used to help prevent infections. This isn't completely unreasonable, though if solid silver metal really good for that reason why isn't it used more often in other medical devices?



I had this set for several weeks before I finally decided on the best way to photograph it. My goal was to get the best rotation video, not necessarily the best single view, so be sure to click the 360-frame or 72-frame turntable icon to see it rotating around a full circle.



That will also let you see the fact that one of the tubes has a little flap hanging in the end in such a way that air can go in, but not out. I immediately assumed this was some kind of torture device, but my medical correspondent Willis reports that it's actually used for people who have functional vocal cords they can breath out through, but for one reason or another they can't draw air back in that way. The flap allows them to breath in through the tube and out through their mouth. (Unless, of course, their head is at the wrong angle, or they are in space, in which case the flap will malfunction.)



Source: eBay seller kiaoradogs

Contributor: Theodore Gray

Acquired: 23 March, 2007

Text Updated: 11 August, 2007

Price: $28

Size: 3"

Purity: 95%

Sample Group: Medical

Irradiated dime.

This dime was briefly radioactive some time in the 1950's or 1960's. A museum operated in Oak Ridge used to have an exhibit, described here in detail, where visitors could have their dimes exposed to neutron radiation, which caused the silver in them to become radioactive for a few minutes. You might think the exhibit was closed due to safety or "what the hell do you think you're doing, are you crazy!?" kinds of reasons, but in fact it was forced to shut down in the mid 1960's when the US mint stopped making dimes out of silver. The neutron activation process used works only with real silver coins.

I suppose by now it probably would have been shut down anyway by namby pambies who think giving visitors radioactive souvenirs is somehow a bad idea, but of course you can still find these all over eBay (something like a million were done over the years). The radioactivity lasted only a few minutes (half-life 22 seconds), so today they are perfectly safe by anyone's definition.

Source: eBay seller danniken

Contributor: Theodore Gray

Acquired: 11 August, 2007

Text Updated: 11 August, 2007

Price: $40

Size: 0.5"

Purity: 90%

Silver bellows.

This strange object was discarded by a research lab: It's old and tarnished, but presumably at one time it was bright, shiny, and expensive. Why someone would make a bellows closed at one end (so you can't even use it as a flexible connector) out of silver is a mystery to me.

If you look at the 3D spin video of this sample you will discover that hidden inside it is a small perforated metal cone, which turns out to be even more exotic than the bellows: It's made of pure platinum (look under platinum to see this object up close). No idea why it's inside, this object was photographed by my assistant Nick. Maybe he left it inside to see if I look at the rotations before posting them? Ha, well, I'll just leave this note here and see if he ever reads my descriptions after I post them.

Source: Anonymous

Contributor: Theodore Gray

Acquired: 2 December, 2007

Text Updated: 8 March, 2008

Price: Donated

Size: 2"

Purity: 99%

Silver leaf in bottle.

This is a little souvenir bottle of silver leaf from a gift shop at the Keystone sky resort in Colorado (nice place, by the way). Silver mining was big in that area, with several towns (Silverthorn, Silverplume, etc) named for it. The amount of silver in this bottle is microscopic because it, like gold, can be hammered into extremely thin leaf form. I have similar bottles listed under gold and copper.

Source: Keystone Resort

Contributor: Theodore Gray

Acquired: 8 March, 2008

Text Updated: 8 March, 2008

Price: $8

Size: 2"

Purity: 95%

Silver-laced bandages.

Silver has anti-microbial properties, so it's not completely silly to make bandages with a small amount of silver dust in them. Considering that this package cost only a dollar, there's surely not very much silver in there, which is probably a good thing as too much can be toxic.

Personally, I'll stick with Neosporin.

Source: Dollar Store

Contributor: Theodore Gray

Acquired: 30 September, 2008

Text Updated: 1 October, 2008

Price: $1

Size: 2.5"

Purity: 99.9%

Reproduction silver medallion.

I got this reproduction of an an early French-American medallion from a silversmith exhibiting at a Renaissance Fair (a gathering of people who like to dress up as people from that or similar historical eras). He had reproductions of several interesting silver artifacts including some he found himself at archaeological digs.

Source: Renaissance Fair

Contributor: Theodore Gray

Acquired: 27 December, 2008

Text Updated: 29 January, 2009

Price: $10

Size: 1"

Purity: 99%

Lab equipment part.

From the source: This is a high-voltage contact from inside a decades-old power supply. I find that ripping apart electronics being thrown away is fabulous as both catharsis after and procrastination from schoolwork, with the added benefit that I occasionally find something incredibly cool, possibly useful, or silver. In this case, its the latter--silver has the highest conductivity of any metal, plus good resistance to tarnish (except around sulfur and sulfur oxides). So while this contact is still quite shiny after decades of existence, the silver sulfide tarnish is visibly building up, albeit long after the useful lifetime of the device itself.

Source: Ethan Currens

Contributor: Theodore Gray

Acquired: 27 December, 2008

Text Updated: 1 March, 2009

Price: Anonymous

Size: 1.5"

Purity: 99%

Silver dollar sputtering target.

What a bizarre, yet perfectly sensible idea. This is a sputtering target, a disk of high-purity silver used in a machine that blasts the surface of the disk with high-energy electrons, knocking loose silver atoms which then travel through a vacuum to be deposed on something you want coated with silver (a mirror for example).

It's also quite obviously an American silver dollar coin, or at least used to be, as you can see from the remainder of the pattern on the surface. Why not? If it's the right size, and it's made of 99.9% (999 fine) silver, no reason it shouldn't work.

Source: Ethan Currens

Contributor: Theodore Gray

Acquired: 28 February, 2009

Text Updated: 1 March, 2009

Price: Confidential

Size: 2"

Purity: 99.9%

Silver thermal compound.

Silver has very good thermal conductivity, so if you're making a paste to aid in heat transfer between a chip and its heat sink, silver seems like a reasonable thing to include in the paste. No idea how much is actually in this stuff.

Source: Radio Shack

Contributor: Theodore Gray

Acquired: 28 February, 2009

Text Updated: 1 March, 2009

Price: $5

Size: 3"

Purity: 10%

Silver oxide battery.

I'm not sure exactly why silver oxide batteries still exist. Lithium cells provide more energy at lower cost, so maybe it's just that there are still devices out there that want the particular voltage the silver batteries provide? I think they are used with hearing aids.

Source: Radio Shack

Contributor: Theodore Gray

Acquired: 2 April, 2009

Text Updated: 7 April, 2009

Price: $4

Size: 0.3"

Purity: <20%

Silver front-surface mirror.

The most reflective of all elements is silver, so mirrors where it is placed on the front surface are the most reflective known objects. Common mirrors where the reflective surface is on the back side suffer from the fact that the light has to go through the glass twice, and are thus much less reflective overall. On the other hand, they don't scratch nearly as easily.

Source: eBay seller bluemedi

Contributor: Theodore Gray

Acquired: 2 April, 2009

Text Updated: 3 April, 2009

Price: $4

Size: 1"

Purity: 99.9%