Better yet, why not have breakable everything? c: It'd be awesome, including the walls. It'd all break at 0.1 pressure
/sarcasm

How about ALMI - Aluminium! It'd melt at 1200C, and conduct electricty!

Just use brick, breakable metal, glass etc. It will do just fine.

But what if we want sand-coloured sandcastles??? </sarcasm>

the sandstone could be used in the creation of concrete or Stone.

it could be a very hard substance that breaks only with lots of pressure.

idk I can't really find anything else.

Good for sand castles

Speaking of which how bout when you mix sand and lets say salt water, you get moist sand that you can use to build structures that will crumble in high heat or pressure.

wat about sand that absorbs water

*coughcoughSPNGcough*

SSTN + PSTE?

thanks for very much info about suggested element