Herkimer Diamonds-Negative Crystals
                        from Herkimer County, New York                                   
Cochise College
Geology Home Page 
Roger Weller, geology instructor  ( wellerr@cochise.edu ) 
Herkimer Diamonds               

last edited:  2/9/17         4 views
Photos are copyrighted by Roger Weller, but can be used copyright-free for non-commercial educational uses.
Just credit photos to R.Weller/Cochise College.

negative crystals within Herkimer Diamonds

     There are two different types of quartz crystal-like inclusions within Herkimer diamonds.  One type
consists of hollow cavities within Herkimer diamonds that have the shape of a quartz crystal.  Some of
these cavities contain water with bubbles and also dark impurities. Other crystal-shaped inclusions may
actually be small Herkimer diamonds enclosed within the larger crystal.  The fact that these small crystals
can be seen within the quartz is unsuspected because should have the same index of refraction.  The fact
that they can still be observed might indicate that quartz does not have a uniform index of refraction but
an index of refraction that varies with crystal orientation.

a very good example of a negative crystal


a closer look at a well-formed negative crystal


a small crystal-like inclusion


a large, irregular inclusion and a small crystal-like inclusion