UNIDENTIFIED MINERAL - GLENTOGHER DONEGAL

Hi all,

Re the attached photo I would be grateful for any guidance that could be offered to help me ID this small orange globular substance/ mineral.

The field of view is approximately 3mm and the other associated minerals are Dolomite and Sphalerite.

Glentogher is a disused lead and silver mine in County Donegal.

Unfortunately I'm still unfamiliar with the minerals associated with such locations so would really appreciate any ideas/ opinions.

Cheers,

Trevor

Hi Trevor,

Based on your images alone, If not sphalerite, I wonder if your "small orange globular mineral" is Smithsonite. This would be my guess. You can try a couple of tests. If you have a UV lamp, it may fluoresce. Also, you might try to dissolve a small grain of this "orange globular mineral" in dilute HCl (muriatic acid). If it's a carbonate like Smithsonite, it should effervesce. Good luck with it.

Ron

Or possibly siderite/rhodochrosite.

A sharper image would be useful, but I agree that it is most likely smithsonite - not dissimilar to that found at Machen Quarry in S Wales. The only qualm I have is that some of the globules appear to consist of stacked crystals which could mean they're hemimorphite, but it's difficult to see clearly.

Pick one off from a non-display area and drop it in dilute hydrochloric acid. If it's smithsonite it will fizz.

Cheers - John

Many thanks gentlemen for your help.

I will try the HCL test and see what happens

I have also attached another photo of the orange material from a different area on the specimen.....might not be any clearer tho! FOV approx 3 mm

I have also attached a photo of another clear micro crystal from the locality - I have already identified Cerussite from the locality but this looks different - is this Cerussite or some other species????? FOV 2mm approx


BIG thanks again.

Trev