Unknown REE, Pyörönmaa, Finland

Second one for the day.

Here is 15 mm prismatic brown crystal in albite from Pyörönmaa pegmatite, Finland.
Pyörönmaa
Attached also two SEM-EDS graphs of two different grain samples. I have difficulties connecting these on minerals listed to locality. Mineral is not particularly difficult to find there. The largest partial crystal found was over 30 mm in size.

Jyrki



Edited 1 time(s). Last edit at 05/11/2012 05:08PM by Jyrki Autio.

Something from a samarskite family. Probably replaced by pyrochlore group mineral.

based on the sem-data I agree with Pavel but the sample looks weird in my experience, could there be a mixup?

cheers

-Johan, there is a possibility of mixup.. I yesterday photographed a different specimen from which EDS grain sample was taken because of the better crystal form. This is the other of actual ones. It is slightly different in color and fracture, but also much larger. Yellowish surface layer looks the same.

Jyrki

this looks more like it

-Johan, do you think the first one could be fergusonite?

please take a few more pictures

Here are two more pictures.

From the list of minerals from Pyörönmaa this could be any of several, for example fergusonite, xenotime, or zircon, depending on what they look like at this locality. doesn't Voorma et al. describe these?
it looks a bit like ytterby zircon

cheers

Hi

EDXA is in accordance with samarskite (the sample in latter pictures.) and it is metamict.

Smaller crystal in first pictures looks like fergusonite told an locality expert.

Cheers