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Pictures of Herkimer Diamonds and their Association with Other Minerals
The General Mineralization Sequence for the Herkimer Diamond Mining District*
Youngest
Oldest
Click on any mineral name to see photos and more information
First Dolomite (small) First Dolomite (small) First Dolomite (small) First Quartz Druze (mostly white) First Quartz Druze (mostly white) First Quartz Druze (mostly white) Chalcedony Chalcedony Chalcedony First Hydrocarbon (thin coating) First Hydrocarbon (thin coating) First Hydrocarbon (thin coating) First Sulfdes First Sulfdes First Sulfdes Second Druze (clear, smoky) Second Druze (clear, smoky) Second Druze (clear, smoky) The Prismatic Druze The Prismatic Druze The Prismatic Druze Strong Hydrocarbon Strong Hydrocarbon Strong Hydrocarbon Seed Crystal Event Seed Crystal Event Seed Crystal Event Herkimer Diamonds Grow Herkimer Diamonds Grow Herkimer Diamonds Grow Herkimer “healing” Herkimer “healing” Herkimer “healing” Three Calcite Events Three Calcite Events Three Calcite Events Weathering Weathering Weathering Second Sulfide Second Sulfide  Second Sulfide
Rust - and related iron oxides
The Main Event
Click next to see dolomite photos
The depositional placement of the second dolomite and third dolomites appear to be happening throughout most of the Herkimer diamond making history, illustrated using the blue arrows. More data is needed because it is difficult to find overlapping relationships with dolomite that let us determine its time of growth relative to other minerals.
*The    mineral    depositional    sequence    is    determined    by    carefully examining   many   specimens,   across   the   entire   district,   to   discover what   minerals   deposit   on   top   of   one   another.      For   example,   calcite   is found   to   grow   over   the   top   of   almost   everything   on   this   list.   Each mineral   event   in   the   above   sequence   varies   in   intensity   across   a deposit,    and    across    the    mining    district    and    thus    lends    a    unique quality   to   each   individual   location   within   the   district.   This   is   the   main reason why mines are different.
Second and Third Dolomite Second and Third Dolomite Second and Third Dolomite Other Minerals Other Minerals Other Minerals
Rare occurrences of strontianite, celestite and chrysocola.
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The information, and photography, on this website is copyright protected by W. David Hoisington, Ph. D. unless another author/photographer is cited.
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Quartz-Hydrocarbon Quartz-Hydrocarbon Quartz-Hydrocarbon
& Crystal Frost
06/16/2018
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New discovery (2016) of microscopic, unusually shaped, crystals at the quartz-hydrocarbon boundary (see Changes at the Boundary)
Last updated January 2018
Thank you Kathryn S. for the donation of 27 samples which were carefully field collected to demonstrate curved features in quartz. 6/30/2018