As hard as ... hydrogen?

At sufficiently high pressure, hydrogen liquefies starting at about 33 Kelvin.(*) That's cold. At about 14 Kelvin and yet more pressure, hydrogen will become a solid. And, it has been theorized since 1935, under enough pressure solid hydrogen can take metallic form.

(*) For mysterious reasons, absolute temperatures are shown in units of Kelvin, and not (as every other temperature scale would suggest) degrees Kelvin.

Not quite this easyHow much pressure? In round numbers, call it five million st...