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Identity HelpUnknown from Greenland

5th Oct 2014 15:16 UTCReiner Mielke Expert

The sample is from here: http://www.mindat.org/loc-30754.html and the blue crystals are embedded in Sorensenite, They are slowly soluble in room temp. concentrated HCl with the release of bubbles ( a carbonate). Hardness is less than 5, I'm guessing around 4. Anyone have any ideas what it might be? The largest crystal cluster is 7mm.

5th Oct 2014 16:44 UTCKnut Eldjarn 🌟 Manager

Fluorapatite.

Knut

5th Oct 2014 21:19 UTCReiner Mielke Expert

Hello Knut,

That is what I thought at first but there is no Nd in it which apatite commonly has as a trace element. Also the material seems to have an excellent cleavage as you can see from the photos which apatite does not have. However I am currently running a test for P so we will see if it is even possible.

5th Oct 2014 21:40 UTCReiner Mielke Expert

Well the phosphate test was positive so it does contain P. It is possible that it is apatite with no Nd although about half the apatites in the world do contain it and the abundance of Nd containing minerals at that locality makes it unlikely that the apatite would not contain some. The big problem is the cleavage. Guess I will have to get EDS done on it to see what is all in it.

6th Oct 2014 00:10 UTCPaul Brandes 🌟 Manager

Fluorapatite is found there and a couple of the photos do indeed look like yours, Reiner.

Get that EDS done and let us know the results...

7th Oct 2014 01:24 UTCReiner Mielke Expert

Someone I won't mention had EDS done on an identical material and the results were compatible with Apatite. Good enough for me. Interestingly when I checked my apatite specimens for Nd only the ones in shades of green had Nd in them, the white, clear, pink, red, and blue ones did not, don't know about purple don't have one. I wonder if the green color is due to Nd?