[Tailback]

Can these diamonds be used to make armor for tanks and apc's? Similar to ceramic armor used now? How about for weapons?

[NYFriend]

If you smack a diamond ring wrong, it will shatter. Not what you want from armor. You'd rather it be soft but not brittle. They won't make good kinetic energy projectiles, because they'd fragment on impact (if they could survive being accelerated) without penetrating. They would also wear the barrel down.

[Sundog]

Possibly, but I've never heard of pieces large enough to use coming out. You would realistically need pieces measured in the tens of inches on a side, and things are still in the tens of carats now. Then the machining task needs to be addressed, since only diamond can be used to machine diamond, in a mutually destructive process.

If you could cast or deposit diamond, that would be a sensational breakthrough.