The well Friedrichssegen, was a mine of silver, lead and zinc and it is believed that the Romans already exploited, although until the thirteenth century there is no written mention of mining in that area, being profitable in the fourteenth and fifteenth centuries, extracting large amount copper and lead in the eighteenth century, but it is in the nineteenth century when coal begins to be extracted from the mine, being famous the discovery of a drusen of 4x3x1 m., which was full of crystals of brown lead ore, the so-called " Emser Tönnchen. " In 1870 more than 200 workers worked in the mine, and a village was created for their families, even the railroad reached the mine in 1880. In 1884 it reached a depth of 483.7 meters; and years later the mine goes into decline, to re-emerge in 1903, buying new machinery and compressed air systems, but in 1913 it was closed for bankruptcy. In 1926, the union "Erzverein Friedrichssegen" resumed the extraction and processing of the ore (with an electromagnetic processing plant) until its cessation in 1928. But in the years 1951-52, a flotation plant for mining was built, and In 1957, when the exploitation of the mine ended, at that time the mine had 22,723 m. of galleries, of which 18,200 m. they were provided with rails for the transport of ore.

Currently the mine has remained as an old mining cemetery, a museum that shows the importance of mining in the area, certain facilities of interest and samples of minerals found there, such as the sample, an aggregate of siderite and rhodochrosite; the first, a fragile iron carbonate, very dark in color due to the content of manganese (manganosiderite), vitreous and pearly gloss, translucent, trigonal crystalline system, with crystals typically of rhombohedral morphology, prismatic or scalenohedral and often massive, and even botroidal ; and the second one is another carbonate but it is a manganese carbonate, normally pinkish, yellowish, brown and even white or gray, with rare transparent crystals, with a pearly, fragile, pearly glassy brilliance and a trigonal crystalline system. The red crystals are those that contain iron; morphologically they are rhombohedral crystals, rarely scalenohedral, also tabular, prismatic and massive crusting, and is even forming botroids. The piece that is presented is of great beauty, rarity, brightness and worthy of any collector.

Acrylic box is included