“Few minerals found in nature are suitable to use unaltered in jewelry. One exception is the "Herkimer Diamond" which forms in vugs of gray rock and are found near Herkimer, New York These are not real diamonds - they are quartz crystals that look like they have been cut & polished like a diamond.”- Rocks for Kids Web page
Herkimer Diamond Mines and the Ace Of Diamonds Mines are the location of unique quartz crystals, the Herkimer Diamond. This site lies at the downrange strike of the Adirondack Mountain PZ ejecta emplacement. We interpret the crystals to be temperature and pressure geomorphosed pure comet silicate. The Mohawk River and its tributaries have eroded the Herkimer accretion formation in this location, exposing the contact face between the ejecta and the underlying bedrock. The hypothesis suggests that this interface layer may have experienced temperature and pressure levels adequate to create these formations of crystals.
Here is a brief overview of the enigma presented by the presence of theses mineralization deposits, as shown from the Herkimer Diamond Mines web site.
The Herkimer Diamond Mines has large abundant elliptical-shaped pockets containing hundreds of Herkimer Diamonds. These pockets vary in diameter from one foot to as large as six feet. It has been suggested that perhaps these pockets were a result of Crypto zone or some other type of plant life being covered by sediments and eventually decomposing, leaving voids in the rock.
The presence of large quantities of anthraxolite in the pockets could also be explained by this theory. It has been proven by laboratory duplication that this coal-like material could be the result of decomposition of plant life.
Now that we have a theory of how the pockets formed, the question arises as to what was the source of the high concentrations of silica. As previously mentioned many theorize that water highly saturated with silica seeped into the pockets and eventually evaporated, leaving the silica deposits to form into quartz crystals. Others have formed a different opinion to what the silica source could have been.
Our interpretation is that the high silica component comprising the "diamonds" is derived from the impacting cometary core. At the interface of comet to terrestrial landscape, great temperatures and pressures are expect to be produced, effectively, a crypto zone. The comet crater excavation process would have offered the terrestrial material - be it plant-life or older carbon formation - necessary for the inclusions.This contact area would most likely land in the up-range segment of a mega ejecta divot. The site of the Herkimer Diamonds find is shown on the next graphic, correlated to the expected emplacement site.
Herkimer Diamond Mine at Adirondack Strike
Another key indication in the description above is the "elliptical shape" of the pockets these minerals are found in. We expect all ejecta from small to mega to be materialized in elliptical shapes.
The Proof set GMY discuses the Gulf of Mexico Yellow PZ sequence that includes the Adirondack Mountains as an ejecta emplacement. Most supportive is the existence of a transitional trenching-to-terminal event, which we interpret as being driven by the comet's trajectory striking the Mexican coastal mountain range after transiting just above the Pacific Ocean. In most circumstances, the Perigee: Zero impacts are to be considered of a low Pressure-Temperature (P/T) event. In this situation, the comet was met with a sudden elevation change and was forced to strike nearly perpendicular to the terrain. The coastal mountains are being driven up by the pacific plate driving under the continent. The passage cut across the Isthmus of Tehuantepec, less than 300 meters in elevation maximum, is the only east-west gap in the range along the plate collision boundary measuring 1 to 2 kilometers in elevation extending for thousands of kilometers. It has been considered as the site for a new east-west transportation conduit, either as a canal or as a rail-link.
Trench cut through the Costal mountain range
Some of the oldest rocks in Mexico are located in the Oaxacan Complex; it contains rocks 900 to 1100 Ma in age (Ortega-Gutierrez,1981). The age corresponds well to that of the Adirondacks, and the entire Grenville complex. Both areas have been found to contain iron, titanium, garnet, quartz and zircons.