FMF - Friends of Minerals Forum, discussion and message board

[Roger Warin]

Hi,
Before returning to more traditional minerals, here is a very rare zinc arsenate. It is from Mapimi, but I do not distinguish between the local normal site Ojuela Mine and the topotype Mine "Flor de Peña", Lampazos, Nuevo Leon.
Paragenesis can help. The secondary mineral seems to be Adamite, I think.
I don’t know that small red spherules. The matrix is limonite.
Thank you for helping me.
Roger.

[Jordi Fabre]

It looks to me as Carminite but this is just a personal impression without any scientific confirmation.

Peter Megaw is a great expert of this mine, hopefully he can see this post...

[Peter Megaw]

The elongate chisel-tipped habit of the legrandite is typical for Ojuela as is the association with adamite. I am not aware of ever seeing adamite on a Flor de Peña piece. Both commonly have rice-grain smithsonite associated.

Carminite is known from both localities...like Jordi, I think that's what's on your piece, but it would take analysis to be sure.

[Roger Warin]

Hello,
Many thanks for these pertinent words.
Here is a drawing with indices corresponding to the position of the crystal in the photo.
Roger.