Late last year we reported on a new find of very fine large specimens of blödite & kröhnkite from Coronel Manuel Rodriguez Mine, Mejillones, Antofagasta Region, Chile.
This locality is an old open cast working for the extraction of copper set in an arid climate on the Mejillones peninsula. The locality is host to a number of sulphate and phosphate minerals including an exceptional recent find of destinezite. Kröhnkite has also been reported from there.
Several kröhnkite specimens have appeared here and elsewhere online, all showing excellent crystallisation, size and at least one with a trapped very dead scorpion.
The presence of the dead arachnid would indicate that the age of the material was comparatively recent, post mining or anthropogenic.
Further discloure on the locality has now been given and this is stated to be a small pond approximately 2.7km from the workings at Coronel Manuel Rodriguez Mine. By the accounts given the locality has now been "collected out".
The "Kröhnkite" Locality Near Coronel Manuel Rodriguez Mine - photo from Roberto Rojas
Although the location looks large, most of the material was contaminated with grit/sand and good specimens were only found towards the centre of the pond.
Since the arrival of specimens to market, some follow up identification work has been completed on both the blue kröhnkite" and the clear to white "blödite".
This work has been carried out independently by seller Ana Cubillo Leivas and on behalf of another by Joy Desor of Mineralanalytik
This work has turned up some suprising but matching results.
The "kröhnkite" has proven to be sal ammoniac with the inclusion of copper ions and the "blödite" being lecontite.
Both of these minerals are ammonium compounds and not currently recorded at Coronel Manuel Rodriguez Mine. As this siite is 2.7km away it is probably correct to refer to this separately.
The origins of a natural source of ammonium to such a high concentration is definitely unusual and worthy of investigation.
I understand the site is going to be visited again for a more forensic study, as and when we hear any news we will update here.
Thanks to Roberto Rojas, Ana Cubillo Leivas, Joy Desor and indirectly Gerhard Möhn for their assistance with this blog/update.
Joy will be publishing a full analysis and comment in his monthly post on Mineralanalytik, I will get a link to this set up when available.
Customers who have bought these specimens on e-Rocks have already been contacted, and we support the right to return for a refund if desired.