There are recent reports of weak ferromagnetism in graphite and synthetic carbon materials such as rhombohedral C(60) (ref.
3
The inclusions in the igneous matrix are unusual in that all possible crystalline morphologies for corundum are present: bipyramidal, prismatic, tabular, and rhombohedral.
4
The crystals belonged to rhombohedral space group R3 with a = 291.4 A and alpha = 61.9 degrees.
5
A remarkable case of enclosed impurities is presented by the so-called Fontainbleau limestone, which consists of crystals of calcite of an acute rhombohedral form (fig.
6
PhMV crystals belong to the rhombohedral space group R 3, with one icosahedral particle in the unit cell leading to 20-fold non-crystallographic redundancy.