FMF - Minerals Forum, discussion and message board

[lluis]

Dear listizens

In 2008 I saw some specimens of the potassium natrium hexafluorosilicate, that all people looked as result of recent human activity.

Now, I see that IMA has aproved it as heklaite.
No doubt that in Hekla volcano this mineral could be present.

But the pieces that are found in Polk County Mine, Florida, should be placed as mineral?
Maybe it has same formula as the natural occuring one, but being those form Polk being the result of human very recent activity, they should be labeled as artificial, or I am lost?

With best wishes

Lluís

[alfredo]

You are right, Lluis. The Florida crystals are, I believe, the result of hydrofluoric acid reacting with clay minerals. The hydrofluoric acid is a waste product of the manufacture of superphosphate fertilizer from Florida's phosphorite rock. The phosphorite is treated with sulphuric acid, which releases the fluorine from the apatite. So calling these crystals a "post-mining" product is a bit misleading - they are "post-chemical treatment". We usually reserve the term "post-mining" for products of natural weathering (oxidation and hydration) of mined material, without any human-added chemicals. Interesting crystals nevertheless.

[Peter Megaw]

Lluis...you are correct... the Florida mineral, impressive for its size and the somewhat scary chemistry of the dumps it grows in...are a man-caused (hence unnatural) artificial analog of heklaite but are not minerals themselves.

[John S. White]

As I understand it, Isaias Casanova is the only dealer selling these specimens and he is quite honest about their origin, he does not represent them as natural.

[Peter Megaw]

You are correct, Isaias has been very careful in that regard, but like the "zincite" crystals from the Polish smelter as these things get farther from the source the more likely that the distinction will be blurred. At least FMF participants will be well educated on the subject going forward.