In my hand is a single vial of Aerogel particles. Aerogel is a porous synthetic material developed by NASA by creating a gel-like substance and then removing it, leaving most of the mass of this substance nothing more than air held by firm scaffolding. This is the lightest material on our planet. It’s nearly as light as air but tough and can sustain pressure of a brick (if in a block configuration).
When you pour some in your palm it’s so light that you cannot feel its weight or it touching your skin, but if you apply pressure by gripping it between your fingers it feels firm. On high pressure you can squash it – it’s brittle and crumbles into fine powder once it loses its structural integrity. You have to be careful breathing as it’s easy to blow away by a light breath.
It’s very expensive.