FMF - Friends of Minerals Forum, discussion and message board

[Paul S]

I recently bought three fluorite octahedrons, without any matrix attached. Now that I'm doing a bit of research on fluorite, I'm noticing not many fluorite octahedrons can be found without a matrix. The seller told me they were natural and from China. I have attached a phote of one of those crystals. I also found out that there is a technique to shape fluorite into octahedrons by hand.

I would like to know if there are any signs to look for, so that I can find out wether these have been chipped by someone to form an octahedron or that they have formed naturally.

[keldjarn]

Natural crystals will usually have growth-patterns on the crystal faces. These can be seen with a loupe or microscope and is very difficult to "fake" on the cleavage planes of fluorite octaedrons. That is what I would look for.
Knut

[Peter]

The "technique"is very simple. People just take any chunk of fluorite and trim to many good locking octahadrons by vleaving along the cleavage planes. The cleaved off pieces is then further trimmed to smaller octahedrons.

[Paul S]

Thanks for the information on the octahedrons, I was able to make a nice photo of one of the faces of the crystal (see attachment). I don't see any of the growth patterns you indicate, only the structure on the photo. Guess I got misinformed on this one.

[Pete Modreski]

Paul,
As I think you have now come to understand, basically all of the low-priced (a few dollars/euros apiece), perfect fluorite octahedrons from China that one sees for sale, have been produced as has been described by cleavage from larger masses of incomplete fluorite crystals.

Another characteristic to distinguish the natural from the cleaved octahedrons; all of the naturally-formed crystals will generally have some area of irregularity at their base, where they were attached to the matrix. If they are only composed of the flat octahedral faces on every side, they are almost certainly to have been produced by cleavage.

Best regards,
Pete Modreski