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Europium is a rare earth that doesn't have a lot of common applications, but the one application where you may have seen it is quite pretty: Glow in the dark paint.
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Glow in the dark powder.
This is strontium aluminate activated with europium. It's a very good glow-in-the-dark material, of the type you expose to light to charge up. It definitely works very nicely in that capacity, and can be charged in just a few minutes under fluorescent light. I got a sample of three different colors on eBay: The seller offers larger quantities and different formulations besides what he sells on eBay.
Not to be confused with our tritium glowing samples, which use the radioactive decay of tritium to glow for 10 or 20 years without any external input whatsoever.
Source: eBay seller teddp
Contributor: Theodore Gray
Acquired: 5 September, 2002
Price: $12
Size: 1"
Purity: <2%
Sample Group: Powders
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 Lump.
This sample arrived with a full set of lanthanides at a time when I was missing europium, terbium, holmium, ytterbium, and of course lutetium.
This very kind donation from Max Whitby of The Red Green & Blue Company in England completed my element collection, to the extent that it gave me a plausible sample of every element one can plausibly have a sample of. (The Red Green & Blue Company is selling a periodic table collection containing similar samples of the same stuff, and if you want a ready-made collection of elements, that's the first place I would look.)
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: 20 December, 2002
Price: Donated
Size: 0.5"
Purity: 99.94%
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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 gasses) 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
Price: Donated
Size: 0.2"
Purity: >99%
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Compact fluorescent bulb.
Some people complain that fluorescent light is "harsh" or "cold" or some such nonsense. The fact is, as long as you have a modern flicker-free high frequency electronic ballast such as you find in almost every compact fluorescent bulb, the light from a fluorescent bulb is far more pleasant and nature than light from an incandescent bulb. Incandescent light is dingy and yellow in comparison. It makes white walls look dirty and faded, and it comes nowhere near approximating the color of daylight, which is the gold standard against which light is judged, because daylight is what we are evolved to like.
This bulb is displayed in my Bulb Stand.
Source: Hardware Store
Contributor: Theodore Gray
Acquired: 28 November, 2003
Price: $3
Size: 6"
Purity: <1%
Sample Group: Light Bulbs
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Hollow cathode lamp.
Lamps like this are available for a very wide range of elements: Click the Sample Group link below to get a list of all the elements I have lamps like this for. They are used as light sources for atomic absorption spectrometers, which detect the presence of elements by seeing whether a sample absorbs the very specific wavelengths of light associated with the electronic transitions of the given element. The lamp uses an electric arc to stimulate the element it contains to emit its characteristic wavelengths of light: The same electronic transitions are responsible for emission and absorption, so the wavelengths are the same.
In theory, each different lamp should produce a different color of light characteristic of its element. Unfortunately, the lamps all use neon as a carrier gas: You generally have to have such a carrier gas present to maintain the electric arc. Neon emits a number of very strong orange-red lines that overwhelm the color of the specific element. In a spectrometer this is no problem because you just use a prism or diffraction grating to separate the light into a spectrum, then block out the neon lines. But it does mean that they all look pretty much the same color to the naked eye.
I've listed the price of all the lamps as $20, but that's really just a rough average: I paid varying amounts at various eBay auctions for these lamps, which list for a lot more from an instrument supplier.
(Truth in photography: These lamps all look alike. I have just duplicated a photo of one of them to use for all of them, because they really do look exactly the same regardless of what element is inside. The ones listed are all ones I actually have in the collection.)
Source: eBay seller heruur
Contributor: Theodore Gray
Acquired: 24 December, 2003
Price: $20
Size: 8"
Purity: 99.9%
Sample Group: Atomic Emission Lamps
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Assorted glow-in-the-dark paints.
This lovely array of glow-in-the-dark (phosphorescent) powders illustrates the range of colors and the brightness of modern luminous paints. Green and aqua are europium doped strontium aluminate, the brightest of all the modern phosphorescent powders. Blue is a alkali earth silicate, while red and orange are older, noticeably less bright zinc sulfides. (The difference in brightness is so great it was difficult to get a photograph that showed the glowing of the zinc sulfide without overexposing the other colors!) The powder packets are meant to be mixed with paint, nail polish, or whatever, rendering them luminous. The bottle in the back is ready-made paint, while the small tub is a heat-and-dip powder.
This set was kindly donated by Ready Set Glo: Visit their website at www.readysetglo.com or their eBay store.
(The "purity" listed below doesn't mean a whole lot since this is a mixture of several different compounds: I'm just indicating that this sample is not a simple element but rather a mixed compound.)
Source: Ready Set Glo
Contributor: Ready Set Glo
Acquired: 15 August, 2004
Price: Donated
Size: 4"
Purity: <50%
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 Sample under oil.
This 5g sample under mineral oil shows the characteristic green oxide coating, as well as some shiny surfaces. Europium is notoriously difficult to keep bright, as it oxidizes in a matter of seconds if exposed to air: This is probably about as good as one can do in a bottle like this. Shinier samples would have to be in a vacuum or inert gas filled glass ampule.
Source: Dave Hamric
Contributor: Theodore Gray
Acquired: 20 September, 2005
Price: $17
Size: .75"
Purity: 99.9%
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Dendritic sample under oil.
This 13g sample under mineral oil shows dendritic crystals characteristic of material purified by some kind of deposition process (either electrolytic or vapor deposition).
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: Dave Hamric
Contributor: Theodore Gray
Acquired: 20 September, 2005
Price: $39
Size: 1"
Purity: 99.9%
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