FMF - Friends of Minerals Forum, discussion and message board

[Josele]

No matter how hard I try, I'm not able to understand this crystal. The smaller at top looks like a cube modified by the dodecahedron. But these triangular faces at reflex, there is a step in the diagonal of a cube face?
Please, if somebody can enlight me...
Thanks.

[marco campos-venuti]

It looks as a purple cube with a clear interior. The two faces are cleavage faces showing the interior of the crystal, cutting two vertex of the cube.

[Bob Harman]

I agree with MARCO. In the southern Illinois fluorite district the locals that had access to fluorite passed the time perfecting their skills cleaving pieces of the mineral into fluorite octahedrons.....fluorite diamonds. They are now commonly available in many different colors and sizes.

The one shown is a partial preferentially cleaved fluorite cube. Partially natural and partially man created. BOB

[Jesse Fisher]

The crystal appears to be a cubic fluorite, which is transparent on the interior with a dark surface layer.. The cube has been cleaved on the octahedral plane (111) on two adjacent sides. revealing the interior and mimicking an octahedral form. It is unlikely that this is the "natural" habit of the crystal.

[Josele]

Oh, now I see it, I had not thought about the possibility of man-made cleaved faces.
Thanks for your help.

[Pete Richards]

Too bad! It would be a magnificent specimen if it was natural. But I agree with the assessments offered. Perhaps there are two more cleavage planes on the back....

The smaller crystals reveal the fakery applied to the larger one.