Pyrosmalite with Magnetite
specimen number:
1052548
location:
Nordmark Odal Field, Filipstad, Varmland Co., Sweden
description: The Nordmark district, located in the municipality of Nord-Odal within Innlandet County, Norway, is historically significant for its production of iron and copper. Geologically, the region is situated within the Sveconorwegian orogenic belt, where mineralization is primarily hosted in Precambrian-aged metamorphic rocks such as amphibolite and gneiss. The ore bodies often consist of magnetite and various sulfide minerals that formed through hydrothermal processes or regional metamorphism of ancient volcanic sequences. Historically, mining activity in the area dates back to the late 1600s and 1700s, with the most notable period of operation occurring during the 18th and 19th centuries to supply local ironworks and smelters. The mines at Nordmark were part of a broader industrial network in southern Norway that utilized the extensive forests for charcoal and local waterways for power. Although large-scale industrial mining ceased by the early 20th century, the district remains of interest to geologists for its classic Scandinavian mineral assemblages and its role in the early development of the Norwegian mining industry. Pyrosmalite refers to a group of rare iron-manganese silicate minerals, specifically broken down into the species ferropyrosmalite and manganpyrosmalite. Geologically, these minerals typically form in manganese-rich hydrothermal environments or as a result of contact metamorphism in iron-manganese deposits. They are characterized by a hexagonal or trigonal crystal system, often appearing as thick tabular or short prismatic crystals with a distinct basal cleavage. Historically, the mineral was first identified in the early 19th century at the Nordmark mining district in Sweden, where its name was derived from the Greek words for "fire" and "odor" due to the chlorine smell it releases when heated. Pyrosmalite specimens are highly valued by collectors for their unique luster and colors, which range from pale green and yellowish-brown to deep brownish-red depending on the iron-to-manganese ratio. Famous localities for well-crystallized examples include the Broken Hill ore body in Australia and the classic mines of the Varmland region in Sweden.
Lustrous brown crystals measuring to 0.5 cm in size rich across the front of this matrix with magnetite. In good condition, a really choice cabinet sized example for this European classic. There are many good crystals across the front of this matrix. The specimen comes with an antique label as shown at the end of the video and dates to the very early 20th century.
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