Druze Quartz from Mines and Deposits in the Herkimer Mining District
The druze quartz is the second mineral introduced into the host dolomitic limestone rocks that are the birthplace of the Herkimer diamonds. It also stops, changes,and then re-occurs, in a series of “phases” In adddition it takes on several different forms (habits, shapes) and colors. Examples of the different types of druze quartz are shown in the slide show below. Descriptions of the “phases” are provided on the right and below.
Click on the button next - to see chalcedony
Phase 1 - the very first quartz crystal event in the Herkimer Mining District. It comes in the shape of tiny pyramid points all connected as a layer, or coating, in a cavity (or vug). Often it It always forms a “rind” contact with the host rock. Most often it is white.
Druze Quartz - Phase One
Druze Quartz - Phase Two
Druze Quartz - Phase Three
Druze Quartz - Phase Four: The Unusual “Seed Crystal” Coating
Phase 2 - this is the third quartz crystal event (after chalcedony) in the Herkimer Mining District and has a form similar to phase one - but it is almost always clear, smoky, or black and never has a rind contact. Sometimes this event will layer directly over the first, making it hard to tell the two apart.
Phase 3 - this druze is very different and easy to identify by its elongated prismatic form (thus named prismatic druze). It also varies dramatically in size, color, and frequency throughout the district. It is likely the precursor to the prismatic quartz (click link).
The last “druze” event in the Herkimer Mining District is a layer of very tiny Herkimer diamonds all cemented together to make a druze. It is not a common occurrence to find this type of druze in contact with the host rock. It is more common to find thousands of tiny Herkimer diamonds scattered over the surface of previously deposited quartz. This will be illustrated on the “seed crystal” page (click button below):
It is difficult to find specimens with multiple druze phases represented and if you do it can be hard to sort them out. It is also important to note that these phases can look slightly different from one mine to another. The photos represent the “best” examples.
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Updated - 03/09/2019
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