I have compiled a list of sources for the elements that are available to the amateur chemist. Gallium will be discussed here.
Gallium is a soft, low-melting metal. It can even melt in the human hand. Gallium is found beneath aluminium on the periodic table. It is silvery gray, just like most metals. Gallium forms colorless trivalent compounds, similar to aluminium. Gallium is moderately reactive and will dissolve slowly in hydrochloric acid, as well as in strong bases. Gallium forms an alloy with indium and tin that is a liquid at room temperature. This alloy is known as galinstan. Gallium is generally found in small quantities in zinc ores. It forms brittle alloys with zinc, aluminium, and many other metals. Because of this, gallium is classified as a corrosive and is expensive to ship legally.
In element form: Galinstan, an alloy of gallium, indium, and tin, is found in Geratherm mercury-free thermometers.
In compound form: Gallium arsenide is used in high-frequency transistors and ICs, as well as in infrared LEDs. Most other LEDs use gallium compounds in some form or another. The inside of the glass bulb on a galinstan thermometer is coated with gallium oxide to prevent the galinstan from sticking.
Here is my sample of gallium. It is a galinstan splat from a galinstan thermometer. I normally store galinstan under water to prevent it from sticking, but it gets a surface oxide coating under water, making it look dull and shapeless. This galinstan was photographed shortly after removing it from the thermometer.