PYRITE
Specimen pyr-106
$ 30.00Dims: 2.40x1.64x1.25" (6.09x4.17x3.18cm)
Wt: 3.71oz (105.2g)
Volga River, Russia
This is a concretion that developed internal cracks as it dried, which developed a coating of metal sulfide crystals. The miner believes that they are simply pyrite, but the gradiations of shapes and colors tell me that there are multiple metal sulfides here, including at the least pyrite and chalcopyrite, but likely also bornite and possibly marcasite. There are areas that are the typical brassy colors of pyrite and marcasite, with two distinctly different forms. There are other areas which have yellow and green irridescent tarnishes like chalcopyrite, and other areas with blue and purple irridescent tarnishes like bornite. In addition, there are areas where the metal sulfide is distinctly red in hue, and I am not sure what this might be.