The rare and heavy gas xenon can be a liquid at room temperature if placed under enough pressure as shown in this little vial. Well, the room would have to be a little drafty to be sure... once the temp goes above 60 degrees (that's 16 Celsius to you non-Americans) then the liquid turns into a gas. A very fun cube to hold and play with. Not too cold where you live? Put it in your fridge for a few minutes and let it warm in your hand to see the transition effect. This xenon sample is embedded in a 2x2 inch (50x50mm) block of crystal clear Lucite acrylic.