Whewellite with Siderite
specimen number:
1052816
location:
Sylvester Mine, Urbeis, Bas-Rhin, Grand Est, France
description: The Sylvester mine, located near the commune of Urbeis in the Ville valley of Alsace, France, was a notable silver, lead, and copper operation within the Vosges mountains. Geologically, the deposit consists of polymetallic hydrothermal veins cutting through Paleozoic metamorphic rocks associated with the Variscan orogeny, featuring primary ores such as galena, acanthite, chalcopyrite, sphalerite, and pyrargyrite. Organized mining regulations were established at the site in 1529, marking the start of a significant sixteenth-century regional mining boom driven by inflows of skilled miners from Saxony and Bohemia. Operations peaked during the sixteenth and seventeenth centuries, making the valley a key silver-producing region in Alsace, with intermittent prospecting and mining continuing until the cessation of primary commercial metal extraction. Whewellite is a relatively rare hydrated calcium oxalate mineral that forms as a low-temperature hydrothermal mineral in ore veins or as a sedimentary authigenic mineral in organic-rich shales and coal beds. It typically occurs as well-developed, colorless to white prismatic or tabular crystals, often showing complex contact twinning. The mineral is named in honor of the English polymath William Whewell and is historically significant for its occurrences in the silver and coal districts of Europe. Dr. Henri Leon Ungemach was a prominent French mineralogist and chemist from Strasbourg who was active in the field during the early twentieth century. Born in 1879, he completed his doctoral thesis on the ore deposits of the Val de Ville in 1907 and went on to meticulously catalog thousands of mineral specimens, specializing in detailed crystal geometry and goniometric measurements. His extensive personal mineral collection, which featured rare European sulfosalts and regional specimens from Alsace, was preserved by institutional museums including the University of Liege and the Natural History Museum of Strasbourg following his death in 1936.
Clear crystalline whewellite across the top of a siderite crystal matrix. Nice old timer from Alsace. The specimen comes with an antique label as shown at the end of the video and dates to the very early 20th century, if not earlier.
Questions about this specimen?
Send an email
or call us: 314-341-1811.