Tennessee Field Diamonds
2
A treasure 485 million years in the
making.
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Weathering of carbonate bedrock
Crystals freed from carbonate bedrock now in
residual clay.
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Quartz crystals in clay residuum. Most crystals in
the Knox dolomites are found on the surface or in
residuum after decomposition of the bedrock

Unusual matrix specimen from Douglas Dam, again found on
the surface after being incorporated in the clay
residuum.

Typical Douglas Dam crystals with black carbonaceous
inclusions.

Large blocky crystals. The broken surfaces show
re-growth of quartz such that the broken crystal, upper
right, must now be held together with poster putty.

Thin prismatic reverse-scepter. This crystal shows
long prismatic quartz deposited over stubby prismatic
quartz, and suggests a more complex paragenesis, as the
most commonly seen order of formation is prismatic
followed by bipyramidal quartz.

Typical black inclusion crystal.


Specimen of elongate quartz showing oriented black
inclusions.

Crystal above, close up.

The black inclusions appear to be hollow, gas filled,
coated with a blackish-brown crust inside.

Parallel chain type morphology.

Large bipyramidal crystal from Douglas Dam.

Large Douglas Dam Crystal

Another large Douglas Dam crystal

One of the largest specimens from Douglas Dam that still
shows good morphology.
Fincher Farm area
(Locality 12)
Kingsport Formation,
Knox Group dolomites.
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This is one of a number of nearby areas
in Greene County.

Fincher Farm shows a great variety of morphologies.
The locality has become picked-over since being listed on
the Internet as a geocache site.

Well-displayed two-stage quartz scepter growth.

Another example of scepter growth, prismatic quartz
followed by bipyramidal quartz.

Example of bipyramidal and skeletal growth.

Multiple parallel bipyramidal crystals.

Large chain-crystal specimen.

Irregularly developed chain crystals.

Large bipyramidal complex crystal

An even larger bipyramidal complex crystal.

This specimen shows two growth stages separated by
corrosion or a dusting of fine fragments.

Another such example.

The hind ends of the two specimens showing
overgrowth morphology.

Low-power photomicrograph. The larger sparkly
fragments are small randomly-oriented quartz crystals.

Another overgrowth specimen.


Bipyramidal over dusted prismatic quartz.

Assymetrical growth indicative of currents during later
development, coming from the left as the specimens are
displayed. The "arm" on the larger specimen is
crystallographically continuous with the rest of the
crystal.
NEXT
Crystals from
a small deposit near
I-81 Exit 8
(locality 10)
Jefferson County, TN
Quartz_crystals_3.htm
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Index
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