Upstate New York Herkimer Diamond formations vary significantly from one
location to another.
Though all are technically metamorphic sedimentary (meaning altered or changed
sediment deposits), each has its own characteristics or 'signature'.
The Fonda location boasts what may be some of the largest of these spectacular
The overall structure of the formation at this location is that of a rippled or
dune-like layered (stratified) limestone bed, with an abundance of vugs, or
pockets, where the crystals have formed, often times completely undisturbed.
What follows is a general description of the Herkimer beds at Fonda where our
Topsoil at the original forest floor - 8 to 24 inches. Many quality crystals can
be collected in the topsoil.
Stromatolites layer - 8 to 16 inches. This stratum resembles a patio constructed
with large blocks, having a space of around an inch between the blocks. The
blocks themselves are very hard, yet porous and rife with mini-pockets up to
about the size of a golf ball. Many high-quality crystals can be found in the
blocks, and in the spaces between.
Shatter rock - 8 to 18 inches. Crumbly in places, can be swept up with an iron
rake. Other sections are quite solid though easily broken up. Sometimes a few
halfway decent specimens show up in the shatter rock, most were formed with
interruptions and imperfections.
In these photos, you can actually see the different layers. These photos are quite old - the claim's footprint is much different now. Most of what you see here is gone.
Caprock - 6 to 14 inches. Fairly hard, mostly barren limestone layer. Riddled
with cracks and moves fairly easily.
Pocket layer or 'goonie layer'. This is where the big ones come from. Ranges
from 16 to 32 inches, most of the crystals are found in the bottom one-third of
the stratum. While this layer has many cracks, it varies from quite soft to
extremely hard material.
Hard rock layer. From 4 to 6 inches thick, a challenge due to the absence of
cracks and the extreme hardness of the rock itself. Barren or nearly so. Some
crystals formed here but are mostly bound to the host and shatter during
Second hard rock layer immediately below that one, this layer even thicker at 6
to 10 inches, likewise almost crack-free and extremely difficult to move. This
is the most daunting layer in the claim.
Drusy layer (yay)! This is the 'fun' stratum. Excellent specimens of drusy
encrusted limestone with water- clear Herkimer points perched on top. Sadly the
layer is no more than 7 inches thick. Thankfully it lifts easily and gives up
its treasures readily.
Second cap rock layer below this, 4 to 6 inches deep. Primarily worthless, not
especially difficult to remove.
Second drusy layer - this stratum is rarely reached by any miner, for the simple
reason that it lies some 12 to 14 feet below the surface. I'm told there's
either drusy in it - or not. And if it's there sometimes it's good. And
sometimes not. We are scratching the surface of this layer after eight seasons
of dedicated excavation.
The claim currently has sections representing each stage. We will surely never get bored!