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Identity HelpLight Blue Mineral with VERY low hardness

11th Jun 2012 05:33 UTCDaniel jacobs

Mineral was found in Portland, Connecticut in 2002.

I tried searching, but there are just too many minerals in that area to pinpoint.

Mineral is brittle, just during the scratching process, 2 small pieces broke off.

Mineral can be scratched by Calcite (3)

Mineral can scratch my fingernail (2)

11th Jun 2012 06:31 UTCVik Vanrusselt Expert

This looks like Calcite to me. Try a drop of acid on it and see if it bubbles.

Vik

11th Jun 2012 08:23 UTCEligiusz Szełęg Expert

blue calcite

11th Jun 2012 08:31 UTCJeremy A. Zolan

This looks like calcite. Try the acid test described above. Slight to moderate effervescence can also be observed if a small sample of the mineral in question is finely powdered and placed in hot vinegar although muriatic acid (HCl) produces a far more obvious result upon reaction with carbonates. Like the peridot you found, I believe this specimen is most likely from a foreign location. I have not seen this habit of calcite associated with central Connecticut pegmatites. Calcite is also quite rare in felsic environments. Be careful...

11th Jun 2012 13:07 UTCUwe Ludwig

Coelestine has a hardness of 3 and shows sometimes a blue colour.

Uwe Kudwig

11th Jun 2012 15:05 UTCJosé Zendrera 🌟 Manager

To me, looks as calcite but could be also celestine (similar hardness, also 3 cleavage planes...).

You can check density to differentiate calcite (2,7) from celestine (3,8) in this easy way:

http://www.mindat.org/forum.php?read,11,250282,250583#msg-250583

11th Jun 2012 20:50 UTCPeter Haas

Do a flame test with one of the pieces that broke off in your scratch test. This should be conclusive enough in this case.

11th Jun 2012 22:07 UTCDaniel jacobs

It is calcite! From Gouvenour NY.. I found a piece of paper deep in my closet. It only makes sense that it is this!