FMF - Friends of Minerals Forum, discussion and message board

[Carles Curto]

Jordi, in the report of Sainte-Maie-aux-Mines at the forum, comments the eclosion on the market of several samples of Austinite from Mapimí. I reed the Austinite had been analized by Peter Megaw, then I really believe they are Austinite. But… they are surprisingly similar, in matrix, presentation, color and crystalline morphology (I had some samples from Jordi in my hands), to some Adamites (cuproadamites) reported by Mineralogical Record, vol. 34(5) of 2003 (Mexico special issue II), page 40, photos 47 and 49, and coincide with a sample I acquired in Barcelona to Natura Kucera in the year 1989 and also with some pictures from MINDAT. From the text of Mineralogical Record I cannot deduce that those Adamites (cuproadamites) were analized. Then may be the samples of the eighteens need a revision?

[Gail]

I looked it over this morning and had a similar thought about this sample too Carles.
How funny that you would voice this today.

[Jordi Fabre]

Still more funny: yesterday I got my own analysis of the Austinite? and the result was not Austinite but cuprian Adamite!

After careful talks with my analyzer and Peter Megaw the conclusion is that on this pocket it should be two different species: colorful bluish-greenish cuprian Adamite with very shiny crystals and very sharp faces and edges, and also Austinite with crusts of green crystals and somewhat elongate chisel tipped crystals.

Peter Megaw said to me:

"The austinites we've examined include botryoidal masses, crusts of green crystals, and somewhat elongate chisel tipped crystals. Some of the blockier "pseudo-octahedral" crystals in your pictures look more like cuprian adamite. We've analyzed as many as we have because we've been going back and forth on this stuff for several years...its almost as if alternating pockets are one or the other. I've seen some pockets with 2 or 3 distinct habits of the same species.
If the pseudo-octahedral stuff IS cuprian adamite it has great color and luster."

So, for me and after both analysis, two different species were mined on this pocket, so in order to clarify the news that I wrote concerning the new Austinite, I already corrected my texts about Ste. Marie Show:
https://www.mineral-forum.com/message-board/viewtopic.php?t=268

Jordi

[Carles Curto]

¡All seems to be clear! I add another picture of cuprian Adamite, also purchased in 1989, that has different characteristics and proceeds from a find of 1988 in the site called “Luga Número Nueve" (lugar Number Nine) on Ojuela mine. Those samples show more clearly isolated crystals of more blue shades.

[Jordi Fabre]

A copy of the analysis of the cuprian Adamite. Note the absence of Calcium, so it can't be Austinite.

Jordi

[marvsT/Nminerals]

Question: In the photo, 8-adam-89-04-2f-pe.jpg, what is the associated brown mineral? Thanks, Marv

[Les Presmyk]

The brown mineral is calcite on iron oxide matrix.