Quartz with Hematite

specimen number:
8311311

location:
Soudan Mine, St. Louis Co., Minnesota, USA

description:

A rare and beautiful specimen from this old locality with gemmy red crystals of quartz to 3.0 cm in length across the top of a hematite matrix. This is in terrific condition. This material is quite old, and very few in this quality were ever found. Previously in the collection of Don Olson.

The Soudan Mine, located in St. Louis County, Minnesota, is the oldest and deepest iron mine in the state, serving as the foundation for the famous Vermilion Range. Geologically, the deposit consists of the Soudan Iron Formation, a Precambrian Banded Iron Formation (BIF) composed of high-grade hematite layers interbedded with chert and jasper. These ores were formed over 2.7 billion years ago through chemical precipitation in an ancient marine environment and were later tilted nearly vertically by intense tectonic forces. Historically, the mine began operations in 1884 as an open pit before transitioning to underground mining to follow the rich hematite veins. It was operated by the Oliver Iron Mining Company and later U.S. Steel until its closure in 1962. Following the end of industrial production, the site was donated to the state of Minnesota and became the Soudan Underground Mine State Park. Today, the mine is preserved for historical tours and has also served as a unique site for high-energy physics research due to its depth and the shielding provided by the surrounding dense iron ore.

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