I have said it before and will say it again. The single most important piece of information for any mineral specimen is where it came from, it’s locality.
Chihuahua is a Mexican State, that adjoins the US States of New Mexico (north) and Texas (northeast), and the Mexican States of Sonora (west), Sinaloa (southwest), Durango (south), and Coahuila (east). It is a large area, just under 250,000 km2.
I have a specimen in my collection labelled simply “Azurite, Cerussite, Chihuahua, Mexico”. Being such a large area doesn’t make this labelling very useful. But it is a specimen that I have had for over 35 years, and that is how it came to me. Back in those days, it was a real challenge to try and get more specific information.
So I set out to try to narrow it down.
There are a number of very well-known mineral localities in Chihuahua including:
The Erupción Mine, Los Lamentos
The Santa Eulalia Mining District
The Naica Mine (famous for the giant gypsum crystals)
Finding localities where azurite and cerussite (and smithsonite which appears to be present but not on the label) occur, shrinks the list of potential localities somewhat.
Additional clues may come from the age of the specimen, the crystal habits, and the matrix.
Given all of this, I suspect, based on information and photos on Mindat, that the most likely locality is Sierra Rica, Manuel Benavides Municipality, Chihuahua, Mexico.
Both azurite and cerussite are recorded. There are also photos with very similar (silica) matrix such as this one. Smithsonite is not specifically listed, but is on one of the photographs in a similar habit as an associated mineral. Perhaps it is not smithsonite, but dolomite, a mineral that is listed!
Let me know what you think!
Below: Azurite, Cerussite, Smithsonite(?), Chihuahua, Mexico. Width of view 6mm.
The contrast in this pic is amazing! 👏🙌👏🙌
I appreciate the pursuit and the problems. I'm to where I actually get (cheap) things with vague localities to play the game of trying to figure it out. All I can contribute to yours is that I also have a nice specimen, ex Peter Megaw, from Sierra Rica, with spherules of azurite and cerussite.