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This gift is perfect for the science buffs in your life. Gallium is an amazing and unique metal that melts when near room temperature, melting at approximately 85o F. Uniquely, it also expands when it freezes, a property few elements possess. It can melt in your hand if left in it long enough. Discovered in 1875 by French chemist Paul Emile Lecoq de Boisbaudran, gallium gets its name from the Latin word for France, which is "Gallia."
Gallium does not occur in large amounts in the natural world but can be found inside medical equipment and various electronic devices. It is used in industry as a semiconductor, which is just a fancy word for something that can sometimes carry electricity if the right conditions are met. Unless you plan on getting this anywhere near an electrical outlet, you and your loved ones should be just fine handling the gallium since it's also nontoxic.
Although it is non-toxic, always wear gloves when handling gallium as it is a skin irritant and is capable of turning your skin gray. Gallium is also very sticky and able to corrode other metals. It actively 'eats' aluminum, so take care. Just a drop is enough to emaciate a soda can. While pure gallium is not harmful, combining it with other substances might be. Avoid mixing gallium with anything unless you are absolutely sure of what you are doing. Be sure to use it on a surface you don't care about, preferably plastic. Gallium sticks to just about anything, so it is better to have it stick to something you could just throw away if necessary. When returning the gallium to its container, do not scrape it off! It will stick to whatever you are scraping it off with. Use heat where possible to get it off.