Cliftonite is a natural form of graphite that occurs as small octahedral inclusions in iron-containing meteorites.
[1] Cliftonite is typically observed in minerals that experienced high pressures.
It can also be synthesized by annealing an Fe-Ni-C alloy at ambient pressure for several hundred hours.
The annealing is carried out in two stages: first a mixture of cohenite and kamacite is formed in air at ca.
[2] The Campo del Cielo region of Argentina is noted for a crater field containing a group of distinctive iron meteorites.