I am not so very sure about how correct this is.
But i remember i read something about diamonds found that they said was made in space without pressure.
If i dont remember wrong, one meteorite with those diamonds landed in Sibir.
But as i say, i am not 100% sure about this.
And when i did a short google search now, i did not see it (i did not look for long)
Thanks for reading, i also ever read about deposit diamond from asteroid but some research said this matter still can not be proven or weak references, so diamond deposit from the asteroid I don't input here.