Siderite on Pyrite pseudomorphs after Siderite with Stannite

Item Description

The Siete Suyos Mine (Seven Servants Mine) in is an old historic Bolivian locality, and according to who you talk to, is sometimes considered to be part of the Animas Mine. This is important to note because it is often difficult to know where specimens are specifically from in Bolivia, because several mines in the area share the same vein system, which is not uncommon as many mines are connected underground within the same orebodies. Fortunately we, directly obtained this specimen from the miner who collected it (back around 2009), so I know for certain where it came from. I honestly have never seen any specimens from this locality before, but I was happy to purchase the pieces I obtained. This piece features a few excellent quality, sharp, gemmy, greenish-brown hexagonal crystals of Siderite measuring up to 1.8 cm which are sitting upon crystals of lustrous brilliant Pyrite (which are actually pseudomorphs after compressed rhombohedra of Siderite), and associated with minor grey crystals of the rare sulfide, Stannite. For Siderite, the quality is good for Bolivia, as I rarely have seen such sharp and gemmy crystals from any Bolivian locality (most Siderites from Bolivia have so much iron content that they're opaque and very dark brown or nearly black). This find was very limited, and after the initial discovery, we never saw them again, so if you're a collector of Bolivian minerals, be sure to pick this one up.
From the collection of Armon McPherson, a retired physicist, now living in New Mexico. Armon received his PhD from North Carolina State University in 1985, and worked at the laser laboratory at the University of Illinois at Circle Center. In the summer of 1997, Armon moved to the Argonne National Laboratory where he worked at the Advanced Photon Source, then the world’s largest synchrotron facility dedicated as an x-ray source. In 2001, he was asked to join a team at Sandia National Laboratories in Albuquerque to conduct laser research for DARPA. Finally, staying within Sandia, he transferred to the Z Facility, the world’s most powerful x-ray facility. He retired in the spring of 2017. Armon's introduction to mineral collecting came in the 1980s during graduate school when he attended his first mineral show. He took up the hobby of faceting gems, and focused his early collection on gem crystals, and later transitioned into collecting non-gem species. We are proud to offer specimens from his worldwide mineral collection here for you.