At the Ward's Open House in Rochester this past Thursday I bought two pieces of Andradite with a label that says "Marron Mine, Colima, Mexico", but I haven't found anything on mindat or elsewhere about this location. Has anyone heard of it?

Do you have any photos of the specimens. There are several localities where andradite is coming from in Colima.
Jean

Hi Jeffrey,

I agree with Jean. Andradite has been noted within the Peña Colorada iron skarn specifically. Here's a paper you may like to browse. [www.geo.arizona.edu] There are many old or obscure named small mines and prospects all over the world that sadly will neither be well noted nor able to be referenced easily. "Marron Mine" could have been named after a prospector or even in reference to the color of the garnets or ore that came from there, we may never know. Bottom line is, there's no substantive reason not to believe the label as found with the specimen, since Andradite is well noted from Colima. You may want to post images of the label and specimen just to help verify that it may be Andradite. Good luck with it Jeffrey.

Ron

Here are some photos. I'm pretty confident it's Andradite, though.

Hi Jeffrey,

Thanks for posting these images. Your specimens are very nice. They look very much like Andradite garnets that would be associated with the setting. There may be some zoning or compositional variation that puts these somewhere in the Andradite-Grossular Series as is noted in the paper referenced above but I think it's probably safe to call these Andradite. Nice specimens Jeffrey.

Ron

Jeffrey,

thanks for the photos, I am assuming that the specimen is wet......the luster is too good.

I have seen similar material from the Pena Colorada Mine in the district of Minatitlan west of Colima. Pena Colorada is a relatively large operation although compared to the Australian or Brazilian operations it is tinny. Regardless, the andradite (andradite-grossular series but likely closer to the Fe bearing andradite) often occur at the contact between the massive magnetite and the fresh limestone. Hence, the surface exposed to the limestone is easy to dissolve in acid. Is there any magnetite leftovers on the "underside" of your specimen?
Cheers
Jean