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Germanium is a lot like silicon: It's a semiconductor from which you can build complex electronic circuits, and in bulk form it's a dark, shiny crystalline yet sort of metallic solid. It's quite expensive, much more expensive than silicon, and not nearly as commonly used.
Germanium can also be used as an x-ray lens, because even though it's opaque to visible light, it transmits and can focus x-rays.
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Small crystal 99.9999%.
Kindly donated by David Franco, who sent many elements after seeing the slashdot discussion.
Source: David Franco
Contributor: David Franco
Acquired: 17 May, 2002
Price: Donated
Size: 0.2"
Purity: 99.9999%
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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: 99.999%
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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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Hyper-pure germanium crystal.
Silicon and Germanium are available in higher purity grades than virtually any other elements. Silicon in particular can be had in large quantities at reasonable prices, at a purity that exceeds anything else achieved by the hand of man. Germanium is similar, just more expensive. The reason for this is not that other elements are necessarily more difficult to purify (some are, some aren't), it's that there is a huge market demand for hyper-pure silicon and to a lesser extent germanium for the semiconductor industry.
Greg sells lots of very unusual elements on eBay and elsewhere: Check the Source link for details.
Source: Greg P
Contributor: Greg P
Acquired: 18 April, 2003
Text Updated: 29 January, 2009
Price: Donated
Size: 1"
Purity: 99.999999%
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Antique-style crystal radio kit.
Heathkit may be out of business but you can still get old and old-style crystal radio kits from www.xtalman.com. I put this one together with my six-year-old: Can you tell? Crystal radios use germanium diodes because they have a lower voltage drop than silicon, and are therefore more sensitive to weak radio signals.
Source: Borden Radio Company
Contributor: Theodore Gray
Acquired: 18 April, 2003
Text Updated: 11 August, 2007
Price: $16.50
Size: 6"
Purity: 99.99%
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IR window.
Germanium is opaque to visible light, but transparent to infrared (heat). That makes it useful for heat-sensing cameras where it can be used to block visible light and make the camera sensitive only to infrared.
Lenses made out of germanium can also focus infrared light, which is neat, but they are very expensive even on eBay. This is just a flat germanium window, such as you might use to cover a CCD for example.
Source: eBay seller ohoa13
Contributor: Theodore Gray
Acquired: 3 June, 2003
Price: $16.50
Size: 1"
Purity: 99.9%
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Cast ingot.
This is a lovely little cast ingot with a broken side that lets you see a different kind of surface. It weighs about 40 grams. Unfortunately, due to a screw up in sample counting, I had to put this sample into the beautiful periodic table display that now graces the Julian Science Center at DePauw University. It's the prototype for a line of museum displays that Max Whitby and I are now building, and being the prototype we made a lot of, um, learning experiences in its construction. One was that the germanium sample that was supposed to go it it was in England at the time, forcing me to take up the slack with this one. Not to worry, Max is sending me more germanium: He buys it direct from China now.
Source: eBay seller kingendymion
Contributor: Theodore Gray
Acquired: 20 June, 2003
Text Updated: 11 August, 2007
Price: $75
Size: 1"
Purity: 99.9%
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 Infrared lenses.
These are very beautiful, very fancy, and normally very, very expensive germanium lenses used to focus infrared light. They are completely opaque to visible light, but transmit heat (infrared light) easily. I bought two on eBay and then, as is my practice, asked the seller if they had any more. He turned out to be very nice and sold me 8 more lenses plus threw in a couple of really nice slabs (see below). Most of them have a chip or two around the edges, which may render them less than useful, and certainly reduce their value a great deal, but for my purposes the chips are if anything a good thing, since they let you see the unique fracture surface (similar to broken silicon). Without the chips these would just be polished blocks of something hard to identify.
They were described as having a thorium coating, which if it's there must be very thin since they register only barely above background radiation levels. Thorium fluoride is used as an anti-reflective coating on infrared lenses, so it wouldn't be surprising if these had such a coating, and it would be very thin.
Source: eBay seller 142pimp
Contributor: Theodore Gray
Acquired: 16 November, 2003
Price: $100/lot
Size: 1.25"
Purity: 99.9%
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Slabs.
I'm not sure what these were made for, but they are rather nice, a bit like single crystal silicon boule slices except made of germanium instead. I got them from a guy I bought a batch of germanium lenses from (see above): He thought I would appreciate them, and I do!
Source: eBay seller 142pimp
Contributor: eBay seller 142pimp
Acquired: 16 November, 2003
Price: Donated
Size: 3"
Purity: 99.9%
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Large ingot.
This ingot is part of a batch Max Whitby got from China for use in his company's element sets and to use in the line of museum displays we are building together. It's a great example of the kind of sample you can get way cheaper if you can buy in bulk from the original suppliers.
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: Max Whitby of RGB
Contributor: Theodore Gray
Acquired: 20 December, 2003
Text Updated: 11 August, 2007
Price: Donated
Size: 2"
Purity: 99.999%
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Bath salts.
"It perspires and is on the beautiful body. To a healthy bare skin..." Oh lordy, the Japanese can be a bit wacky sometimes. This is something meant to be put in your bath water to, I don't know, infuse it with germanium or something.
Source: Japan
Contributor: Theodore Gray
Acquired: 15 December, 2006
Text Updated: 29 January, 2009
Price: $20
Size: 8"
Purity: <20%
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Bath bar.
Similar to the bath salts described in the previous sample, this is some kind of Japanese ceramic/germanium thing meant to be used in a bath. What exactly the 99.999% refers to I am not clear, but I doubt it's the purity of the germanium.
Source: Japan
Contributor: Theodore Gray
Acquired: 15 December, 2006
Text Updated: 20 February, 2008
Price: $20
Size: 8"
Purity: <20%
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Germanium button.
Description supplied by the source:
This germanium button was melted from standard 5N+ pure melt stock in an vacuum arc melter- the germanium and surrounding crucible were heated much more than was necessary to melt the small blob, so that the rate of heat loss was slower and greater crystalline structure had time to develop. Although this is the same purity of material that is used to grow the oft-seen trapezoidal monocrystalline bars of germanium, arc melting is of course much more of a chaotic, disruptive, and impure process, where large crystalline grains are not present to the extent that the purity of the original melt stock would allow for. Nevertheless, crystals resembling ice on a window pane are visible on the surface, as I had hoped for when melting it.
Source: Ethan Currens
Contributor: Ethan Currens
Acquired: 21 March, 2008
Text Updated: 21 March, 2008
Price: Anonymous
Size: 0.75"
Purity: 99.99%
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Broken sputtering target.
Description supplied by the source:
This is a fractured piece of germanium from a sputtering target that was melted, machined, polished, put into service, and then apparently broken during use after not too long. The silver-looking material on the back is, in fact, silver in an epoxy matrix. Depending on the particular process being used, some sputtering systems use the target as an anode, and thus they must be conductive. For metal targets, indium or gallium/indium eutectic is commonly used to 'glue' the target to its backing plate and provide a good electrical connection. However, those two only 'infiltrate' and glue metal to metal effectively, so epoxy with dispersed silver particles is generally used for targets made of intrinsic semiconductors like germanium or any number of other uses where indium or liquid metal alloy would be inappropriate for whatever reason. However, for sputter systems or anything else that will be used in a high vacuum environment, one has to be very careful about what materials are employed, especially with organic glues and gaskets, because many materials are porous to gases or will outgas themselves at .00000000001 atmospheres.
Source: Ethan Currens
Contributor: Ethan Currens
Acquired: 21 March, 2008
Text Updated: 21 March, 2008
Price: Anonymous
Size: 1.5"
Purity: 99.999%
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Germanium mineral supplement.
For people who think eating germanium is healthy. I don't.
Source: eBay
Contributor: Theodore Gray
Acquired: 11 March, 2009
Text Updated: 12 March, 2009
Price: $20
Size: 2"
Purity: 99%
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Gallium Germanium Alloy.
This is a small crystal of gallium-germanium semiconductor alloy pulled by the Czochralski process. The bubbles on the surface are a defect that may explain why this sample ended up in the surplus market.
Source: SoCal (Nevada), Inc
Contributor: Theodore Gray
Acquired: 10 February, 2007
Text Updated: 10 February, 2007
Price: $15
Size: 1"
Composition: GaGe
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Renierite.
Description from the source:
Renierite ((Cu,Zn)11(Ge,As)2Fe4S16 tetr.), Kipushi, Shaba, Dem. Rep. of Congo. Perfect example, with brown-orange-reddish cristalline masses. 1,5x1,2x1 cm; 3 g.
Source: Simone Citon
Contributor: John Gray
Acquired: 28 January, 2009
Text Updated: 29 January, 2009
Price: Trade
Size: 0.6"
Composition: (Cu,Zn)11(Ge,As)2Fe4S16
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