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Identity HelpOxidized Pyrite?

16th Nov 2019 19:09 UTCClark James

02749870015739312259619.jpg
I just received these pieces from a friend who found them while hiking near Banff, Canada. It appears to be pyrite, yet it seems to oxidize red. Is this common?

16th Nov 2019 19:10 UTCClark James

00677310015739313897482.jpg
Additional image.

16th Nov 2019 19:21 UTCAlan Pribula

Very common.  The red-brown coating is mixed iron oxides/hydroxides formed by the reaction of the pyrite with atmospheric oxygen and water.  The coating is usually referred to as limonite, and it normally consists primarily of the mineral goethite, with other iron species also often mixed in.  Sometimes the pyrites are converted totally into limonite, forming a pseudomorph.

16th Nov 2019 20:42 UTCClark James

Great! Thank you for the information.

16th Nov 2019 23:03 UTCKeith Compton Manager

Nice representative specimen. Perhaps if you know the exact location, you should add to mindat.
 
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