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Identity HelpPyrite on Cobaltoan Calcite?

8th May 2018 23:46 UTCBrian Greenstone

I got this piece over the weekend out of a collection being sold, but it had no tag. It looks like pyrite on cobaltoan calcite, or possibly pink smithsonite (due to the ridges on the crystals). I couldn't find any references to either combo, so figuring out the locality has been difficult. Can anyone here help positively ID the mineral and locality for me?

Thanks,

-Brian

9th May 2018 01:19 UTCKevin Conroy Manager

Is there a label on the front of the plastic stand?

9th May 2018 02:16 UTCThomas Lühr Expert

I can read/guess there "pyrite on fluorite".

Not sure if "fluorite" is right. A drop of acid will tell. Surely not smithsonite.

9th May 2018 03:05 UTCBrian Greenstone

No, ignore the label on the stand. It is incorrect.

Almost certainly cobaltoan calcite, but from where? I can't find any others like this for comparison.

-Brian

9th May 2018 03:05 UTCBrian Greenstone

Oh, the collection it came from was predominantly Chinese minerals, so that's a good starting point for this.

9th May 2018 05:15 UTCDana Slaughter 🌟 Expert

Pyrite on fluorite--Xiefang mine, Jiangxi Province, China. Most came out at least a few years ago and I snagged perhaps a half dozen, including some to over a foot across from a Tucson wholesaler.

9th May 2018 06:13 UTCAlfredo Petrov Manager

I agree with Dana - Looks more like fluorite than cobaltoan calcite. But as Thomas said, you can prove it for yourself with a drop of acid.

9th May 2018 11:00 UTCEd Clopton 🌟 Expert

Check specific gravity: smithsonite = 4.3-4.5; calcite = 2.7; fluorite = 3-3.2. Looks like there's not enough matrix (or pyrite) to throw the measurement too far off. That plus the acid test should settle it, although locality still would be a mystery.

9th May 2018 12:27 UTCBrian Greenstone

Thanks, Dana! That looks like a match!

9th May 2018 19:50 UTCVolkmar Stingl

Clearly fluorite with pyrite, most probably from China. Found some very similar ones there by myself.

10th May 2018 03:18 UTCKeith Compton 🌟 Manager

Sounds like the label attached to the base was correct