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Identity HelpLime Green Minerals (Found in CT in beryl mines)

10th Jun 2012 21:05 UTCDaniel jacobs

These were recovered from a beryl mine in the middlesex county area of Connecticut. (Portland or East Hampton)


They are lime green in color


I dont know if they are part of the beryl, but I would think not because the beryl recovered was either golden or more emerald in color.

10th Jun 2012 21:34 UTCStephanie Martin

Hardness?

10th Jun 2012 21:42 UTCGeorge Creighton

Might be shards of chrysoberyl, but need to know the hardness as Stephanie requested.


Good luck and welcome to the forum.


Regards george

10th Jun 2012 21:52 UTCAmanda Hawkins

They look like Peridot to me :-)

11th Jun 2012 00:06 UTCDaniel jacobs

Stephanie Martin Wrote:

-------------------------------------------------------

> Hardness?



I dont know much about hardness, but I did a little research on the hardness scale and checked to see if it could scratch quartz(7), and it could not, I tested it on a piece of green calcite(3), and it did scratch it. Then I tested it on Fluorite(4), and it also scratched it.

11th Jun 2012 00:28 UTCRowan Lytle

did you collect them? if so, PM me exactly where from and I can tell you what they might be.

11th Jun 2012 03:40 UTCPaul Brandes 🌟 Manager

They look a lot like the peridot you find in the San Carlos basalts in Arizona.


Daniel, you may want to do a mineral search on Mindat to see if any of these potential minerals occur in Connecticut and if any are near you.

11th Jun 2012 03:51 UTCDaniel jacobs

I tried searching at the specific mines that I went to, but there are very few pictures uploaded. Ill do a little more research

11th Jun 2012 04:00 UTCStephanie Martin

The hardness test you did rules out chrysoberyl (which is confirmed found in Connecticut) and any mineral that is harder than quartz. Without a good crystal termination or cross section it is difficult to determine. An SG test would be useful in this situation. Perhaps even a streak test? Hopefully Rowan will be able to nail it for you.


regards,

stephanie :-)

11th Jun 2012 04:03 UTCDaniel jacobs

It really does look like peridot to me.... however. There are no such occurrences of peridot in connecticut. Perhaps I am the first? I do have a good eye ;-)

11th Jun 2012 05:36 UTCJohn M Stolz Expert

I thought Peridot also, ut purely from color which isn't very reliable. You need more data points. Try a pen knife (hardness 5.5) and a steel file (7) to get a better idea. Peridot is around 7.

11th Jun 2012 05:44 UTCDaniel jacobs

John Stolz Wrote:

-------------------------------------------------------

> I thought Peridot also, ut purely from color which

> isn't very reliable. You need more data points.

> Try a pen knife (hardness 5.5) and a steel file

> (7) to get a better idea. Peridot is around 7.


Hmmmm. Since you said that I tested it on pyrite (6.5 - 7) and the mineral couldnt scratch the pyrite cube or quartz.


the pyrite couldnt scratch the mineral back... BUT quartz did leave a faint mark.


I retested it on Fluorite(4) and the mineral DID scratch the fluorite(4).


So the hardness must be between 6-7...

11th Jun 2012 08:25 UTCJeremy A. Zolan

The occurrence of peridot in a felsic pegmatite seems unlikely to me however I agree that the proposed identity of this mineral seems fairly accurate. Be careful, as it may very well be a specimen with a foreign origin that was disposed of at the collecting site. This situation is commonly encountered and can make things quite confusing both mineralogically and geologically!

12th Jun 2012 16:43 UTCJim Bean 🌟

Beryl, in between green and golden would be my guess based on the (typically inexact) hardness tests and color. I agree with Jeremy, a beryl-bearing pegmatite is a highly unlikely environment for peridot.
 
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