HerkimerHistory.com

The best website on "Herkimer Diamonds"

This site was last updated on June 2010
Definitions and Scope:

Information and Mineral Sequence for Diamond Acres (DA), Fonda, NY

Diamond Acres is the area that this author has visited the most, going back to the early 1970's.  More than 40 "pockets" of crystals have been discovered over the decades and several different mineral zones explored resulting in a large Herkimer collection.  The examination of this collection gathered, plus many field trips to collect specimens looking for the "missing links", and wisdom from "old timers", has resulted in the mineral sequence diagram below.  There are also photos, maps, and resources for the collector wishing to go digging for "Herks" (to be added).
This Herkimer diamond deposit has a small fee for collecting.  It also has areas where people have paid to "stake a claim".  You may not collect on other people's claims without their permission.
A public service project always open to input  from the community interested in Herkimer diamonds.
Photographs illustrating each mineralization phase:
"In place" pocket and location photographs:
Maps and Directions:
Tip and resources for diamond digging at this location:
For now - Go to the Crystals link at the top of the page. Photo donations are needed to help here!
For now go here ->
For now go here ->
Information is currently being collected for this webpage.
Web page author - W. David Hoisington, Ph.D.
Photographs of "common" crystal habits largely unique to this location:
These are two photos sent in of a Herkimer crystal group specimen, locally called "goonies". What is nice about these two photos is that they show the "common" habit for the larger quartz crystals at this location - which are also unique to this location.
The photo on the right is the top view of the above specimen (which showed the bottom view).  Note that the faces are mostly flat and shiny.  The holes directly facing once had dolostone in them like shown in the above picture, indicating a contact with the host rock.  The crystal contains many internal fractures creating "rainbows" and there are patches of smoky color. All these features are characteristic for this location - as is the size 10 inches along the length of the specimen! (25 cm)
Notice the rounded off sandy dolostone on the photo to the left.  Good evidence of weathering.  (note --------------->
These pieces of rock are where the crystal made contact with the cavity in which it "grew" and thus encapsulated the wall rock. It is characteristic for this location. Thanks to Linda Grindstaff (2008) for both of the photos.
To see example photos of each of these mineral phases, please go to the general mineral sequence disgram and click on the mineral you want to see.                      Click "minerals" --------->

Note that there is a photograph below of a small protected "valley" in pocket wall rock that shows a little of what it might have looked like before weathering.

Scroll down.

The photo to the right is of a different specimen, but still from a pocket containing these large Herkimer diamonds (the point of a crystal is shown on the right).   Of all the Herkimer deposits, weathering effects are most dramatic at Diamond Acres.  Yet it is likely the wall rock was, at one time, covered with crystals - similar to what we see in fresh surfaces at other mines.  A hint of this is shown at the arrow where this sandy dolostone has a coating of crude dolomite crystals.  Such examples of what the "original" wall rock in these large pockets might have looked like are not easily found at this location.

The smooth, weathered, sandy dolostone is shown bottom center and is like the material in the above two pictures.

Specimen collected and photographed 2008, Dr. D.

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Every mineral phase has its own web page.  These seperate pages can be accessed from the minerals link ------->

There are some phases for Diamond Acres which have yet to be photographed: 1) the large pyramidal phase and 2) the 3rd calcite phase.  The pyramidal phase is dificult to find at Diamond Acres and usually is sparse and small (see photos of pyramidal druze - druze page).     The third phase calcite is very weathered and is nearly unrecognizable.  Perhaps some lucky collector will discover some tucked away in a protected vug.

First phase calcite (and second phase) photos can be found on the "with other minerals" page ------->

We do not have any good photos of skeletal crystals from Diamond Acres, although we have seen examples of them in the field.   The habit is not as well developed as in other locations and it it likely quite hard to photograph.   Photographs or specimen donation, even "junk" ones, of this habit are welcomed.   We have not see any hopper crystal development from Diamond Acres, but if you have personally collected one we would love to hear about it.

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