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Gallium is used in high-speed semiconductors and LEDs in the form of gallium arsenide. As an element, it is a soft, very low-melting metal. So low-melting that it will actually melt in your hand if you hold it long enough. It's also essentially non-toxic, so you wouldn't hurt yourself doing this. Unfortunately, it stains your hands and is hard to get off, so I don't recommend it. In fact, it stains or sticks to just about anything, which is very irritating because it would otherwise make a very nice substitute for mercury where a liquid metal is called for.
By mixing gallium and indium it's possible to make an alloy that is liquid at room temperature, just like mercury, but the alloy is also annoyingly sticky.
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  Round ingots.
Purchased by Ed from Randolph Zerr, estuff@aol.com, on eBay in May 2002. Ed had been thinking about a puzzle where the trick would involve melting some gallium by holding the puzzle in your hand long enough. He now finds that it takes way too long before your hand actually melts the gallium.
Source: eBay seller estuff
Contributor: Ed Pegg Jr
Acquired: 8 May, 2002
Price: $50/20 grams
Size: 0.5"
Purity: >99%
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Akihabara.
Please excuse my fiction, after 259 factual descriptions, something had to snap.
"Not now mama, I need more diodes!" the young boy shouted as he ran out the door and down the steps of his family's small apartment in the neighborhood of Tokyo known as Akihabara Electric Town. Her request, whatever it was, had scarcely registered with the boy. His only concern was getting to the market before his favorite diode vendor went home for the night.
In the light rain the impossible beauty of neon playing off the wet streets enveloped him in its electric warmth. He walked happily, the arcs guiding him without thinking towards the layers, tunnels, and warrens of shops that were e-town. Approaching the entrance, he brushed aside the hanging wires like vines over a cave. (The stall by the door sold patch cords of all lengths and descriptions, which was rather of a nuisance from a practical point of view, but quite wonderful in the way it defined the passage from outside to inside.)
To some people the rows and rows of stalls selling every kind of electrical component, subassembly, tool, and connector might have seemed chaotic, with parts spread out in bins like fruits at the farmer's market. Those people had best stay on their side of the hanging wires, inside was not a world for them. Inside the boy walked down the aisles, turned right at the capacitors, left at the toothless old man still selling variable inductors, seeing in each stall the pattern and meaning of its array of goods.
Some shopkeepers were already closing their shutters, but familiarity let him look through them to the parts he knew lay inside, just as he could look through the metal and plastic cases of the components themselves, seeing without seeing the junctions, gaps, dielectrics, fields and forces that gave them their function.
He hurried, knowing that if he got there in time, the diode man would stay late for him, as late as it took, patiently showing him how the latest new types worked, their strengths and weaknesses, their phosphors. Yes, their phosphors, for these were no ordinary diodes. They were light emitting.
It never occurred to the boy that the diode shop stayed open late only for him. And it registered only dimly that when he was there, the man ignored his other customers, or hurried them off with a quick word and perhaps a too-good price. The diode man knew, sensed, that this scrappy boy was someone to be reckoned with, someone not to be taken lightly, someone whose questions needed to be answered.
Of course the diode man couldn't have known, nor could anyone have known, that thirty years later that boy, working in one of the great electric industrial firms born and bred in the neighborhoods around Akihabara after the war, would make the final breakthrough that pulled the plug on neon, mercury, and tungsten light. The breakthrough pinhead that took in thirty watts of electric power and turned it into twenty-nine point nine watts of the purest white light. The breakthrough that briefly sent the price of thulium through the roof until people realized there were plenty of new sources now that anyone cared to find them. The breakthrough that let us paint our walls with liquid light, more radiant, more beautiful, more magical even than the sheltering neon he would remember reflecting off the streets and sidewalks of his boyhood in Akihabara.
But that was all for the future. Today he needed blue. Not just any blue, but the right blue to balance the spectrum of his latest light bulb and bring out the pale violet of his mother's flowers. Two hundred yen, but worth it for a good blue. The kind of blue you get only from gallium.
Source: Theodore Gray
Contributor: Theodore Gray
Acquired: 3 October, 2002
Price: $40
Size: 1"
Purity: <1%
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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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100g from larger lot.
I purchased 500g of gallium for use in the series of museum displays I am helping build with Max Whitby of The Red Green and Blue Company: This 100g vial full was the tax I extract on all element samples that pass through my hands. I plan to use some of it to make a room-temperature liquid gallium-indium alloy.
To extract this quantity from the larger vial full, I simply placed the big vial in a cup of hot water for a few minutes, then poured the liquid metal into the glass vial sitting on a balance, pouring until the balance read 100g more than the tare amount. The melting point of gallium is rather low, you see.
Source: eBay seller kingendymion
Contributor: Theodore Gray
Acquired: 20 June, 2003
Text Updated: 11 August, 2007
Price: $57
Size: 1"
Purity: 99.99%
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Galistan thermometer.
Mercury thermometers have fallen out of favor especially for home use because mercury is toxic and thermometers are made of glass, which tends to break. Alcohol thermometers can be used, but for those who prefer a liquid metal look, a recent invention is the "galistan" thermometer, which uses a patented eutectic alloy of gallium, indium, and tin, liquid down to below the freezing point of water. (Which means there's no problem using it to measure the temperature of anyone who isn't dead.)
This patent explains all about the alloy and its advantages in the construction of thermometers.
Unfortunately, like all gallium-indium alloys, it's kind of sticky, which makes it much less fun to play with than mercury. It's also hugely more expensive, which isn't a problem for the tiny amounts needed in a thermometer, but is a big problem if you want to make a few pounds of it to play with.
Source: Grocery Store
Contributor: Theodore Gray
Acquired: 10 November, 2003
Text Updated: 11 August, 2007
Price: $5
Size: 5"
Purity: >65%
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 Dali cube.
This cube was made from my stock of gallium, which is appreciating in value rapidly (in 2005). It was cast as a perfect 1" cube, then carefully precision-melted on one corner to make a demonstration of the low melting point of gallium. It must be kept in an air conditioned environment at all times: If the climate control in my office ever fails over the weekend, we'll know it if there's a puddle in place of the gallium cube sample.
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: Theodore Gray
Contributor: Theodore Gray
Acquired: 21 May, 2005
Text Updated: 4 May, 2007
Price: $60
Size: 1"
Purity: >95%
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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.
This coin has a unique complication: It melts at slightly above room temperature (29.8C, 85.6F). It arrives sandwiched between a pair of ice packs in an insulated box, along with a warning to keep it cool at all times (I'm keeping it in an unheated basement rather then with the rest of my collection, which is in an office building that would quickly reach the melting point of gallium were the power to fail for any length of time in the summer.) Needless to say, gallium is not likely to catch on as a metal for coinage, except maybe on Pluto.
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: 29 January, 2009
Price: $29
Size: 0.75"
Purity: >99%
Sample Group: Coins
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Semiconductor grade gallium.
Extremely high purity (6 nines) gallium, presumably for the manufacture of gallium arsenide chips.
Source: Ethan Currens
Contributor: Theodore Gray
Acquired: 24 March, 2009
Text Updated: 24 March, 2009
Price: Anonymous
Size: 3"
Purity: 99.9999%
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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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Etched gallium arsenide wafer.
Unlike all my other integrated circuit wafers, this one is incredibly thin. Watch the rotation video to see how delicate it is (and in fact it's cracked in several places, though it's still hanging together, implying that the metallization layers are strong enough to keep it intact even though the substrate is broken).
Remarkably, you can actually see the etching of the circuits from both sides, meaning that the gallium arsenide crystal substrate must be incredibly thin. I don't know how this is done, or why.
Source: SoCal (Nevada), Inc
Contributor: Theodore Gray
Acquired: 24 February, 2007
Text Updated: 24 February, 2007
Price: $19
Size: 4"
Composition: GaAs
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Gallium Arsenide Microwave Amplifier.
This is a Celeritek CTR-990126 CPW microwave transceiver, and there's a stunningly beautiful little city inside. The input and output are not wires: They are waveguides, hollow tubes that the signal travels through as an electromagnetic wave. You can see the miniature antennas that pick up the signal from the waveguide at the bottom left and right of the picture, or at the top and bottom of the Spin video.
Look at the next sample to see the circuitry up close.
Source: eBay seller time-warp
Contributor: Theodore Gray
Acquired: 24 March, 2009
Text Updated: 25 March, 2009
Price: $50
Size: 4"
Composition: GaAs
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Gallium Arsenide Microwave Amplifier.
This is one of the micro-circuits inside a Celeritek CTR-990126 CPW microwave transceiver seen up close (see previous sample for an overall view).
At microwave frequencies the shape of everything matters, and signals a nearly as happy to travel through air as they are through wire. Notice how in some places the signal path clearly continues across gaps where there is no wire: Interwoven loops of wire act like transmitting and receiving antennas, or if you will like capacitors, that are able to pass only very high-frequency signals.
I'm not an expert in microwave circuitry so I can't tell you exactly what each of these components is, but somewhere in there are gallium arsenide transistors and diodes.
Source: eBay seller time-warp
Contributor: Theodore Gray
Acquired: 24 March, 2009
Text Updated: 25 March, 2009
Price: $50
Size: 4"
Composition: GaAs
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