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Shiny! Chromium is just incredibly shiny, and many of the shiny things in our world are shiny because of chromium. It's plated on car bumpers, plastic toys, and just about anything else you can think of. As a shiny element, chromium is almost unbeatable: It's cheap, easy to electroplate, does not corrode, and of course, it's very shiny. Silver is shiny too, but it tarnishes quickly. Platinum is shiny and doesn't tarnish, but it's expensive. Rhodium is used for plating jewelry, but I'm not sure why, because it doesn't look any shinier to me. Maybe it's just because too many chemical engineers got slapped after bringing their wives an experimental chrome plated ring.
While everyone has seen chromium plated objects, bulk solid chromium is very uncommon. There's just no reason to want something made out of solid chromium, because usually a few microns on the surface is plenty: Solid chromium wouldn't be any shinier, and it would be a lot more expensive. In fact even though thousands of tons of chromium are mined and plated onto products every year, almost none of it ever exists as lumps of solid chromium: It is turned into chromic acid as it is extracted from the ore, then shipped to electroplating companies in that form. There's just no reason to ever turn it into metal before it's plated onto something like a car bumper. This is a pity, because it means finding some unused scrap chunk of chromium to use as an element sample is almost impossible.
Did I mention it's very shiny?
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 Small crystal lumps 99.9%.
Kindly donated by David Franco, who sent many elements after seeing the slashdot discussion. Very attractive little bits of metal!
Here is a joke about Chromium, one of the few known element jokes:This guy goes into his dentist's office, because something is wrong with his mouth. After a brief examination, the dentist exclaims, "Holy Smoke! That plate I installed in your mouth about six months ago has nearly completely corroded! What on earth have you been eating?"
"Well... the only thing I can think of is this... my wife made me some asparagus about four months ago with this stuff on it... Hollandaise sauce she called it... and doctor, I'm talkin' DELICIOUS! I've never tasted anything like it, and ever since then I've been putting it on everything... meat, fish, toast, vegetables.. you name it!"
"That's probably it," replied the dentist "Hollandaise sauce is made with lemon juice, which is acidic and highly corrosive. It seems as thought I'll have to install a new plate, but made out of chrome this time."
"Why chrome?" the man asked.
"Well, everyone knows that there's no plate like chrome for the Hollandaise!"
Source: David Franco
Contributor: David Franco
Acquired: 17 May, 2002
Price: Donated
Size: 0.3"
Purity: 99.9%
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Electroplated foil.
This is a thin foil of chromium electroplated on nickel foil, from the Flex-n-Gate manufacturing plant in Urbana, Illinois.
My van had broken down (bad battery) and I was waiting at Peter B's repair shop for them to put in a new one. I noticed I was sitting with nothing to do just across the street from what bills itself as the largest manufacturer of automotive bumpers in the country, Flex-n-Gate. I immediately thought CHROMIUM and took a walk over to their front office.
The receptionist seemed a bit confused about who she should direct me to, but finally went in back to find an engineer: Presumably she thought he would at least know what I was talking about.
The engineer, Douglas Suits, was very understanding, and I showed him some photographs of the Periodic Table on my PowerBook. He said he would check around for some samples, and later that day I went back to pick up an envelope containing this flake for chromium and two very nice chunks of nickel (see).
Unfortunately, while they receive nickel in metallic form, chromium arrives in the form of chromic acid because that is more convenient for electroplating. So while they probably have more chromium in one place than almost any other place on earth, he was unable to give me any. They have so much nickel they actually have to keep a guard on it because of its value, but presumably no one wants to steal chromic acid!
He explained that bumpers are actually not primarily plated with chromium but rather with nickel. They electroplate 0.0010" of semi-bright nickel, 0.0003" of bright nickel, and only 0.000000066" of chromium onto the base of steel.
Source: Flex-n-Gate, Inc
Contributor: Flex-n-Gate, Inc
Acquired: 25 April, 2002
Price: Donated
Size: 0.3"
Purity: >99%
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Granular powder.
This is a nice dense granular powder of metallic chromium. Weighs more than you'd expect for a powder.
Source: Mark Rollog
Contributor: Theodore Gray
Acquired: 20 July, 2002
Price: $8
Size: 0.01"
Purity: >99%
Sample Group: Powders
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Vapor grown crystals.
These small crystals came with a helpful little card, which states as follows: "These crystals are produced in a high vacuum chamber. The chamber is heated to the point where the metal vaporizes and sublimates onto a glass substrate."
Source: SoCal (Nevada), Inc
Contributor: Ed Pegg Jr
Acquired: 5 August, 2002
Price: $10
Size: 0.1"
Purity: >99%
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Sample from the RGB Set.
The Red Green and Blue company in England sells a very nice element collection in several versions. Max Whitby, the director of the company, very kindly donated a complete set to the periodic table table.
To learn more about the set you can visit my page about element collecting for a general description or the company's website which includes many photographs and pricing details. I have two photographs of each sample from the set: One taken by me and one from the company. You can see photographs of all the samples displayed in a periodic table format: my pictures or their pictures. Or you can see both side-by-side with bigger pictures in numerical order.
The picture on the left was taken by me. Here is the company's version (there is some variation between sets, so the pictures sometimes show different variations of the samples):
Source: Max Whitby of RGB
Contributor: Max Whitby of RGB
Acquired: 25 January, 2003
Text Updated: 11 August, 2007
Price: Donated
Size: 0.2"
Purity: 99%
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Sample from the Everest Set.
Up until the early 1990's a company in Russia sold a periodic table collection with element samples. At some point their American distributor sold off the remaining stock to a man who is now selling them on eBay. The samples (except gases) weigh about 0.25 grams each, and the whole set comes in a very nice wooden box with a printed periodic table in the lid.
To learn more about the set you can visit my page about element collecting for a general description and information about how to buy one, or you can see photographs of all the samples from the set displayed on my website in a periodic table layout or with bigger pictures in numerical order.
Source: Rob Accurso
Contributor: Rob Accurso
Acquired: 7 February, 2003
Text Updated: 29 January, 2009
Price: Donated
Size: 0.2"
Purity: >99%
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 Shiny crystals.
These shiny crystals were formed by slow electrodeposition, and are in needle, plate, and octahedral forms.
Source: Warut Roonguthai
Contributor: Warut Roonguthai
Acquired: 5 May, 2003
Price: Donated
Size: 1"
Purity: 99.999%
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Electrowinning plate.
This is almost certainly a plate that came from the electrolytic extraction of chromium from its ore, or from an electrolytic purification process. Chromium was dissolved in a solution and electricity was used to plate it out onto an electrode. The only difference between this and electroplating such as is done with car bumpers, etc, is the goal: In this case you don't care if it's pretty or shiny, you just want to plate out all the chromium so you can use it for something else.
Source: eBay seller akilawolf
Contributor: Theodore Gray
Acquired: 5 June, 2003
Price: $10
Size: 1.5"
Purity: 99.9%
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Great huge rings of solid chromium.
This is a sputtering target made by the TOSOH corporation, used to deposit chromium on something by vacuum sputtering, discarded as scrap by some company in southern California, and then bought from a scrap metal yard by John Wechselberger, the source of some of my largest bulk samples of semi-exotic metals.
When I first saw them, I had grave doubts that they could be solid chromium, despite all assurances that they were. But one crack with a sledge hammer proves that they are not stainless steel with a thin layer of chromium as I had suspected: They are pure solid chromium through and through, as evidenced by the broken crystal surface, which looks nothing like steel. (And by the fact that I could break them at all: These are 3.75 pound monsters disks that would have been extremely strong if they were any kind of steel.)
I have four such disks, which I think is a tremendous lot of chromium! They are stamped "Cr-2N8", which almost certainly means 99.8% pure. Notations such as 3N5 or 5N are commonly used to mean 99.9% or 99.999% respectively. They were probably hot isostatically pressed (hipped) or sintered from chromium powder, then machined.
Source: John Wechselberger
Contributor: Theodore Gray
Acquired: 18 August, 2003
Price: $20/disk
Size: 7"
Purity: 99.8%
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Broken plate.
This is chromium electrowinning plate from the electrolytic purification of chromium. Why it was discarded (and then bought up by John Wechselberger from a scrap yard) I don't know, because it looks like very nice stuff. I got these directly from John, but the source is listed as his eBay partner, because that is where you can get some of your own from.
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: eBay seller akilawolf
Contributor: Theodore Gray
Acquired: 21 August, 2003
Text Updated: 4 May, 2007
Price: $5/pound
Size: 0.75"
Purity: 99.9%
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Arc melted button.
I've been experimenting with a very crude arc melting furnace made from a box of firebrick, an old 275A stick welder, two graphite electrodes, and a small graphite crucible. I melted this button of solid chromium down out of a small pile of the chromium plate described above. Not bad for a $15 furnace (not counting the welder).
Source: Theodore Gray
Contributor: Theodore Gray
Acquired: 23 August, 2003
Text Updated: 26 April, 2007
Price: $5/pound
Size: 3/4"
Purity: 99.9%
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Canadian Nickel.
Canadian quarters were made of nickel until about 2000, so naturally they had to find something else to make nickels out of. This 1952 Canadian nickel is chrome plated over a steel base.
Source: Andrew Goodall
Contributor: Andrew Goodall
Acquired: 1 November, 2003
Price: Donated
Size: 0.6"
Purity: 5%
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Phonograph needles.
Before CDs made the whole subject boring, people went to a lot of effort to get good sound reproduction and long life from their audio recordings, which at the time involved a physical needle being dragged through a groove that wiggled back and forth in the shape of the sound wave to be reproduced. It worked surprisingly well all things considered, but the needles did tend to wear out, so people worried about what they were made out of and what damage they were doing to the grooves when they become worn.
I imagine these chromium ones were fairly low-budget compared to the osmium and iridium needles I have, and of course eventually diamond tips become the standard, before everyone lost interest when CDs came out.
Source: eBay seller donfriend
Contributor: Theodore Gray
Acquired: 25 November, 2003
Price: $16.50/24
Size: 0.5"
Purity: 90%
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Broken and polished plate.
This lovely, and quite substantial, 1/2" thick slab of chromium is NASA surplus. Not sure what they were doing with it, but I'm sure it was exciting and involved trips to mars or something. It came with two sides coated with thick green oxide. I've never quite understood why chrome (and ferrochrome) is found with this kind of oxide on it. Chrome does not oxidize on its own in air: People electroplate it onto steel precisely because it stays shiny indefinitely. The slab must have been exposed to either chemical or electrolytic attack at some point.
At Ethan's urging I machined, lapped, and polished one face to a mirror finish. This is appropriate since so much of chromium's uses involve putting a mirror finish on something that normally doesn't have one.
Source: Ethan Currens
Contributor: Ethan Currens
Acquired: 1 July, 2006
Text Updated: 19 November, 2007
Price: Donated
Size: 2.5"
Purity: 99%
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Briquette.
Looking rather like a small charcoal briquette, this object is made of relatively pure chromium, and is used in analytical metallurgy. For what I am not privy.
Source: Ethan Currens
Contributor: Ethan Currens
Acquired: 30 October, 2006
Text Updated: 19 November, 2007
Price: Donated
Size: 1.5"
Purity: 99.8%
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Partially polished slab.
This huge, thick, heavy slab of chromium has a crusty greenish layer, visible on the bottom in this picture, and covering the whole back side if you look at the rotation video. This is not, as one might think, chromium oxide (which is green) but rather a coating of glass used as a lubricant during the extrusion process. The slab is heated to red heat and dipped in powdered glass to form the coating. The notion of glass as a lubricant might seem strange, but at high temperatures, why not? Juan kindly ground and polished half of one side to show how pretty chromium gets when you give it a mirror finish.
Source: Juan Jimenez
Contributor: Juan Jimenez
Acquired: 12 May, 2007
Text Updated: 14 May, 2007
Price: Donated
Size: 12"
Purity: >99%
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Beautiful crystals.
These are probably electrodeposition crystals, though they may be vapor deposited. Very shiny, my prettiest chromium sample for sure.
Source: Juan Jimenez
Contributor: Juan Jimenez
Acquired: 12 May, 2007
Text Updated: 12 May, 2007
Price: Donated
Size: 1"
Purity: >99.9%
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Chrome plated gummy bear.
So, I took my whole family to Switzerland for a couple of weeks last summer. It was quite a lot of fun especially since there were no fatalities. We did many different things, and of course in Zurich this necessarily included shopping: You've got to hand it to the Swiss, they know how to get your money. (Full disclosure, I am technically a Swiss citizen, so I'm allowed to say bad things about them.)
Just down the alley from our hotel was a gummy bear shop, which quickly became one of the kids' favorite attractions. Yes, an entire store that sells only gummy bears, nothing else (OK, they had gummy giraffes too, but you get the idea). Up at the checkout counter where they had the various gummy bear related trinkets I found this lovely metal, almost certainly chrome plated, gummy bear key chain.
Source: Switzerland
Contributor: Theodore Gray
Acquired: 19 November, 2007
Text Updated: 19 November, 2007
Price: $5
Size: 1"
Purity: >95%
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Broken sputtering target.
Description supplied by the source:
This piece was broken from a 4N pure sputter target. Both machined and broken surfaces are visible, although the broken ones are much more beautifully crystalline in structure.
Source: Ethan Currens
Contributor: Ethan Currens
Acquired: 21 March, 2008
Text Updated: 21 March, 2008
Price: Anonymous
Size: 1.5"
Purity: 99.99%
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Partially melted plug.
Description supplied by the source:
This is a formerly machined and threaded chromium plug of some sort. Its purity is 3N, so it was partially melted down in a vacuum arc furnace in order to use it as a custom alloy additive- you can see a little bit of copper from the crucible in which is was melted on the top flat face. What probably happened was that there wasn't perfect contact between the piece and the crucible, resulting in an arc which flash-vaporized a tiny amount of the copper crucible. As for its origin, the original melting company has no idea what it was used for originally and neither do I--massive chunks of pure chromium are pretty scant, the two main examples being electrolytically deposited anodes and sputter targets, of which this is neither.
Source: Ethan Currens
Contributor: Ethan Currens
Acquired: 30 April, 2008
Text Updated: 30 April, 2008
Price: Anonymous
Size: 1"
Purity: 99.9%
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Chromium oxide green.
Cr2O3 is used as a green pigment in paints and ceramic glazes. This is the pure powder form.
Source: Pottery supplier
Contributor: Theodore Gray
Acquired: 28 February, 2009
Text Updated: 1 March, 2009
Price: $10
Size: 2"
Purity: 68%
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Car bling.
This is a chrome-plated plastic propeller designed to be mounted on the back of a trailer hitch that is not currently being used to pull a trailer. Presumably it spins in the wind as you're driving.
Source: Farm & Fleet
Contributor: Theodore Gray
Acquired: 21 April, 2009
Text Updated: 21 April, 2009
Price: $20
Size: 7"
Purity: <1%
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Chromium Petrified Wood.
The tag that came with sample reads as follows:Jurassic, Arizona USA
This wood has been minerally replaced with Chromium giving it a green color. Very little of this wood has ever been found, making it very rare. This wood is a natural hygrometer, when dry it becomes a very light pale green and when wet or exposed to humidity it turns a deep green.
Source: Fossil Image Ltd.
Contributor: Theodore Gray
Acquired: 29 March, 2003
Price: $15
Size: 2"
Composition: Cr
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Ferrochrome crystal.
Ferrochrome is an alloy (mixture) of iron and chromium. It is a common intermediate material between chromium ore and finished products involving iron and chromium, such as the common high strength chrome-vanadium steel. I believe that it is simple cheaper and easier to ship ferrochrome to customers rather than try to refine pure chromium, which would just end up getting mixed with iron again anyway: No sense spending a lot of time and money purifying something that isn't going to be used in pure form anyway.
This is a very lovely crystal, heavy and mineral-like, though it is an artificial product.
Source: eBay seller valdor
Contributor: Theodore Gray
Acquired: 3 June, 2003
Price: $10
Size: 2.5"
Composition: FeCr
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Ferrochrome lump.
Ferrochrome is an alloy (mixture) of iron and chromium. It is a common intermediate material between chromium ore and finished products involving iron and chromium, such as the common high strength chrome-vanadium steel. I believe that it is simple cheaper and easier to ship ferrochrome to customers rather than try to refine pure chromium, which would just end up getting mixed with iron again anyway: No sense spending a lot of time and money purifying something that isn't going to be used in pure form anyway.
This is a lumpy solid, not as nice as the crystal above, but still satisfyingly heavy.
Source: eBay seller valdor
Contributor: Theodore Gray
Acquired: 3 June, 2003
Price: $5
Size: 2"
Composition: FeCr
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YAG boule top.
YAG stands for yttrium-aluminum-garnet: It's used to make lasers and can be doped with various elements to create different colors. This green one, for example, is doped with chromium.
The conical shape is similar to that of my silicon boule top, presumably because they are made by similar crystal-growing procedures. A crystal begins growing from a seed, expands out until it reaches the diameter of the melting pot is being pulled from, and then continues to grow as a straight-sided cylinder as it is pulled slowly out. Only the full-diameter portion of the rod can be used, so the cone at the start becomes waste and ends up with someone like me. (Actually, even this waste is quite valuable, probably because it can be melted down and reused. But Max found a nice company willing to sell us the cutoffs for a reasonable price.)
Source: Max Whitby of RGB
Contributor: Max Whitby of RGB
Acquired: 10 October, 2003
Price: Donated
Size: 2"
Composition: (Cr,Y)Al2O3
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Encrusted ferrochrome crystal.
This ferrochrome lump came along with some much larger ones (see listings), and it's interesting because on the back side (click one of the rotation links to see it from all sides) it's heavily encrusted with some kind of green material. My guess is that it's chromium oxide, which is green, how it got there I don't know.
Source: mrx
Contributor: mrx
Acquired: 15 July, 2005
Text Updated: 20 June, 2007
Price: Trade
Size: 4"
Composition: FeCr
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Invar block.
Invar is an alloy of primarily iron (64%) and nickel (36%), known for is unusually low coefficient of thermal expansion. This makes it useful for precision instruments and measuring devices that should as much as possible remain the same size and shape at all times. This block would be excellent for smashing such a precision instrument into a tangle mess of broken gears and dials. It weighs about 13 pounds and appears to have been roughly cut with a large band saw.
Source: eBay seller boss1
Contributor: Theodore Gray
Acquired: 19 June, 2007
Text Updated: 20 June, 2007
Price: $60
Size: 10"
Composition: FeNiCCr
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Crocoite.
Description from the source:
Crocoite (Pb Cr O4 mon.), Adelaide Mine, Dundas, Tasmania, Australia. Classic red orange elongated crystals on limonitic matrix. 7x4,5x3 cm; 72 g.
Source: Simone Citon
Contributor: John Gray
Acquired: 30 September, 2008
Text Updated: 1 October, 2008
Price: Trade
Size: 2.75"
Composition: PbCrO4
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Crocoite And Cr-Cerussite.
Description from the source:
Crocoite and Cr-cerussite (Pb Cr O4 mon. ; Pb CO3 with Cr orth.), Dundas, Tasmania, Australia. Small, distinct orange Crocoite crystals with yellowish Cromecerussite on matrix, very rich in Cr this example! 6,5x2,5x1,5 cm; 20 g.
Source: Simone Citon
Contributor: John Gray
Acquired: 28 January, 2009
Text Updated: 29 January, 2009
Price: Trade
Size: 2.6"
Composition: PbCrO4 +PbCO3(Cr)
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Uvarovite.
Description from the source:
Uvarovite (Ca3 Cr2 (Si O4)3 cub.), Outokumpu, Finland. Rich association of chrome silicates (Uvarovite, Cr-diopside, Cr-tremolite). 6,5x6,5x2 cm; 136 g.
Source: Simone Citon
Contributor: John Gray
Acquired: 28 January, 2009
Text Updated: 29 January, 2009
Price: Trade
Size: 2.6"
Composition: Ca3Cr2(SiO4)3
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Chrome-vanadium steel socket.
This hex socket (used with a handle to tighten or loosen hex nuts) is made of steel with a small percentage of chromium and vanadium to strengthen the alloy. For some reason nut- and bolt-related tools (socked sets, crescent wrenches, adjustable wrenches, spanners, etc) seem to have "chrome vanadium" and "Cr-V" stamped on them at a much higher rate than other tools, even though similar alloys are no doubt used for many other tools. It's probably a historical thing.
Source: Farm & Fleet
Contributor: Theodore Gray
Acquired: 8 February, 2009
Text Updated: 8 February, 2009
Price: $1
Size: 1"
Composition: FeCrV
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Chrome Vanadium Wrench.
Many tools are made of chrome-vanadium steel, an alloy that is tough, hard and not too expensive. Typical alloys contain about 1% chromium and a few tenths of a percent of vanadium.
Source: Hardware Store
Contributor: Theodore Gray
Acquired: 28 February, 2009
Text Updated: 1 March, 2009
Price: $8
Size: 8"
Composition: FeCCrV
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Chrome Vanadium Wrench.
Many tools are made of chrome-vanadium steel, an alloy that is tough, hard and not too expensive. Typical alloys contain about 1% chromium and a few tenths of a percent of vanadium.
Source: Hardware Store
Contributor: Theodore Gray
Acquired: 28 February, 2009
Text Updated: 1 March, 2009
Price: $8
Size: 8"
Composition: FeCCrV
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Chrome-vanadium steel socket.
This hex socket (used with a handle to tighten or loosen hex nuts) is made of steel with a small percentage of chromium and vanadium to strengthen the alloy. For some reason nut- and bolt-related tools (socked sets, crescent wrenches, adjustable wrenches, spanners, etc) seem to have "chrome vanadium" and "Cr-V" stamped on them at a much higher rate than other tools, even though similar alloys are no doubt used for many other tools. It's probably a historical thing.
Source: Farm & Fleet
Contributor: Theodore Gray
Acquired: 8 February, 2009
Text Updated: 8 February, 2009
Price: $1
Size: 1"
Composition: FeCrV
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Huge pile of bumpers. (External Sample)
The local bumper factory in my town used to send their mistakes to Macros Scrap Metal. It must have been a really bad day at the factory to create this huge pile of chrome-plated car and truck bumpers. You cannot begin to imagine how dazzlingly bright this pile was in the blazing sun on a cold winter's day. Sadly, Macro's contract with the factory requires them to destroy all the bumpers, so I was not able to take home a sample.
As is typical of chrome plated objects, nearly all the metal you see in this picture is chromium, yet chromium represents only a minuscule fraction of the total weight of the objects, because it is nothing but a thin plating on the outside.
Location: Marco's Scrap Metal
Photographed: 18 January, 2000
Text Updated: 8 February, 2009
Size: 180"
Purity: 0.001%
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