# Why does it require so much pressure to create diamonds?

Why does it require so much energy/pressure to create diamonds, yet with silicon it is very easy and (I believe) naturally occurs in a "diamond" structure, i.e. where each atom is covalently bonded to four adjacent atoms? I guess it has something to do with the fact that the outer shell is further away from the nuclear, since that is the only significant difference between the two atoms, but I can't work out why that should matter here.

• In short, carbon loves to form $\pi$ bonds, but silicon doesn't. – Ivan Neretin Aug 30 '18 at 7:16
• If you squeeze hard enough on silicon, it transforms to an hcp structure. Why is that so hard, when titanium is hcp at STP? – Jon Custer Aug 30 '18 at 12:57
• Secondarily, silicon does not occur naturally with the diamond structure. It does not occur naturally as the pure element at all, only combined with oxygen. – Oscar Lanzi Aug 31 '18 at 0:11