This natural pyrite “sun” hails from Sparta, Illinois.
Measures approximately 4” x 3” and weighs 4.3oz
The pyrite suns at Sparta are found in Pennsylvanian-age rocks, approximately 300 million years old, 200 to 250 feet below ground in coal mines that extract the Herrin coal. The flashy pyrite disks are found a few inches above the coal seam in thin, pyrite-rich shale layers in the roof. The roof rock that hosts the pyrite disks is a black, organic-rich marine shale called the Anna Shale, which is widely traceable from Indiana to Kansas. In the mines around Sparta, scraps and thin sheets of roof shale will naturally fall from the roof, or are preemptively pulled down by miners for safety, and can reveal disks of pyrite.*
*courtesy of Illinois State Geological Survey