Colorado Gem & Mineral Co. - Rocks for the Rest of Us

Pyrite Concretion

Pyrite Concretion
Dimensions: L: 4  x  W: 2.5  x  H: 2.5
Locality: Dongchuan District, Kuming Prefecture, Yunnan Province, China
Item: 5239
Weight: 0.00
Availability: In Stock
Price: $110.00
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Very large concretion with distinct layers of pyrite crystals. How these formed is really unique. Bubbles of HS gas (from rotting organic material in the mud) at the bottom of a sea(later forming black shale) reacted with the iron and solidified in the mud, later to be found as concretions in the black shale. There won't be a lot more of these because they are found only at the exposures on the contact between layers.
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