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Selenium used to be used in rectifiers, before the development of semiconductor-based diodes. They were big old things that didn't work very well (see picture below). These days selenium is in the news primarily when some place gets too much of it in the soil or water (either naturally or as a result of industrial dumping). People or animals eating plants grown in such soil can develop serious medical problems. On the other hand, selenium is also an essential nutrient with a minimum recommended level of 50mcg/day. It's all a question of quantity.
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Small button 99.999%.
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: 0.1"
Purity: 99.999%
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  Rectifier.
Before the invention of silicon and germanium rectifiers, these were state of the art. Despite being called "miniature" rectifiers, they are huge by current standards!
Source: Charles Cowie
Contributor: Charles Cowie
Acquired: 9 September, 2002
Price: Donated
Size: 2.5"
Purity: >90%
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Hunks.
These are bigger hunks of selenium from Canada, about 20 grams each. They are nondescript as elements, but do illustrate what a wonderful place eBay is to deal with. The first one failed to arrive after a while, so I emailed the seller asking if it had been sent. He assured me it had, but offered to send another if it didn't arrive soon. It didn't, and he did. Naturally not long after that, the first one arrived in a torn, dirty envelope postmarked almost a month before that looked like it had been opened, but still contained its lump. The replacement arrived the next day. People on eBay are just the nicest people you'd ever want to meet.
Source: eBay seller kingendymion
Contributor: Theodore Gray
Acquired: 27 September, 2002
Price: $26
Size: 1.5"
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: 99.5%
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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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Pretty cast ingot.
Dave Hamric sells elements on his website and on eBay. He donated this beautiful cast ingot of selenium as an example of the sorts of things he can supply.
Click the source link for more information about his offerings.
Source: Dave Hamric
Contributor: Dave Hamric
Acquired: 9 July, 2003
Price: Donated
Size: 1.5"
Purity: >99%
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Photocopier drums.
These are old scrap photocopier drums sold for their aluminum value. I got them, however, for their selenium content. Selenium compounds are photo-sensitive, and form the basis of all modern photocopier (Xerox) machines, as well as all laser printers. The drum is charged with static electricity and then exposed to the image to be reproduced. Where light strikes the drum, the static is dissipated. Then the drum is dusted with toner, which sticks only where there is static.
Source: Marco's Scrap Metal
Contributor: Theodore Gray
Acquired: 15 August, 2003
Price: $1
Size: 12"
Purity: <10%
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Old light meter.
This is one of a batch of three old photographer's light meters I got on eBay: From the paperwork that came with them, it looks like people sent them in for repair at a certain shop, paid for the repairs, but never claimed the meters. That was 30 years ago, so I guess the shop can be forgiven for giving up hope on them.
The neat thing about selenium light meters is that they require no batteries: The selenium sensor works like a photocell to generate its own electricity. This meter, having been repaired only 30 years ago, works perfectly.
Source: eBay seller beaglemania2
Contributor: Theodore Gray
Acquired: 15 August, 2003
Price: $7
Size: 4"
Purity: <10%
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Rectifier.
Before the invention of silicon and germanium rectifiers, selenium was used to convert AC to DC. It worked only marginally well compared to modern silicon components.
Source: eBay seller radiocorner
Contributor: Theodore Gray
Acquired: 25 November, 2003
Price: $10/24
Size: 2"
Purity: >90%
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Rectifier marketing brochure.
This is a great example of marketing. Basically, selenium rectifiers are really not that good. But, they were better than the alternative vacuum tube technology, so a company that made them got the idea that people could go around replacing burned out rectifier tubes with selenium rectifiers. This brochure is full of detailed technical information about how to do this for particular kinds of tubes, certain brands of radios, etc. It even includes a price list, which indicates that these things cost about a dollar, which was of course worth a lot more then than it is now. A modern silicon rectifier that works far better can be had for a few pennies: As part of an integrated circuit the price of an individual rectifier would be essentially zero.
Source: eBay seller nrankscs
Contributor: Theodore Gray
Acquired: 3 January, 2004
Price: $4
Size: 11"
Purity: 0%
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Technical grade beauty.
I've never seen selenium this pretty, I had to double check that it wasn't actually germanium or silicon, which it strongly resembles. But no, it's actually technical grade (meaning not overly pure) selenium crystal.
Source: Ivan Timokhin
Contributor: Ivan Timokhin
Acquired: 4 September, 2007
Text Updated: 11 November, 2009
Price: Donated
Size: 1.25"
Purity: 99%
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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: 24 December, 2007
Text Updated: 24 December, 2007
Price: $22
Size: 0.75"
Purity: >99%
Sample Group: Coins
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Brazil nuts.
Brazil nuts (which are not nuts and don't come primarily from Brazil) have an elemental peculiarity: There are extremely high in selenium, even when growing in soil that is not particularly rich in that element. It is said that a single Brazil nut gives you your daily requirement of selenium (which is admittedly pretty small).
Source: Walmart
Contributor: Theodore Gray
Acquired: 28 February, 2009
Text Updated: 1 March, 2009
Price: $3
Size: 2"
Purity: 0.003%
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Brazil nuts.
Brazil nuts (which are not nuts and don't come primarily from Brazil) have an elemental peculiarity: There are extremely high in selenium, even when growing in soil that is not particularly rich in that element. It is said that a single Brazil nut gives you your daily requirement of selenium (which is admittedly pretty small).
Source: Walmart
Contributor: Theodore Gray
Acquired: 28 February, 2009
Text Updated: 1 March, 2009
Price: $3
Size: 2"
Purity: 0.003%
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Selenium-red glaze on vase.
The seller described this as a SCHEURICH vase from the 1970's. Whatever that is I don't know, but they also said it had a selenium glaze, that's good enough for me.
Source: eBay seller camillehervier
Contributor: Theodore Gray
Acquired: 24 March, 2009
Text Updated: 24 March, 2009
Price: $40
Size: 12"
Purity: <5%
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Generic dandruff shampoo.
Selenium sulfide is used in dandruff control shampoos. This is a generic variety that actually uses the chemical's name as its main identity.
Source: Walmart
Contributor: Theodore Gray
Acquired: 24 March, 2009
Text Updated: 24 March, 2009
Price: $5
Size: 7"
Purity: 0.5%
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Selenium toner.
Back in the dark ages photography involved soaking paper in a series of strange chemicals to make images appear on it. This 22g/l solution of sodium selenide was apparently one of them.
Source: eBay seller 20fec
Contributor: Theodore Gray
Acquired: 24 March, 2009
Text Updated: 24 March, 2009
Price: $15
Size: 10"
Purity: 1%
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Selsun blue shampoo.
Selenium sulfide is used in dandruff control shampoos. No doubt the "Sel" in "Selsun" comes from this ingredient.
Source: Walmart
Contributor: Theodore Gray
Acquired: 24 March, 2009
Text Updated: 24 March, 2009
Price: $5
Size: 7"
Purity: 0.5%
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SnSe sample.
From the source:This sample of tin selenide was prepared in the course of semiconductor research, about 35 years ago. Many selenides, sulfides, and tellurides are all candidate semiconductor materials, due to their small band gap energies. That this is a brittle and crystalline intermetallic can be clearly seen from the surface texture and fracture marks.
Source: Ethan Currens
Contributor: Ethan Currens
Acquired: 8 May, 2007
Text Updated: 1 March, 2009
Price: Donated
Size: 1"
Composition: SnSe
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Native Selenium.
Description from the source:
Native Selenium ( Se trig.), Anna Mine, Alsdorf, Germany. Distinct crystals on matrix! 3,5x2,5x1 cm; 22 g.
Source: Simone Citon
Contributor: John Gray
Acquired: 10 January, 2009
Text Updated: 10 January, 2009
Price: Trade
Size: 1.4"
Composition: Se
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