Polyhedroid Agates Page 1
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          (center top specimen photo from 2009 Gem Shop Calender)
Polyhedroid Agates are one of nature’s great unexplained formations. These geometric beauties were only found for a short time in
the 1970’s and only in one location in the world. It is fitting that some of the most desirable agates in the world come from the
greatest agate producing country, that being Brazil. These were located in Paraiba the only state in Brazil that ever produced any of
these specimens. These stunning agates formed in geometric pattern shapes rather than the more common round or oval agate
shape. The theories of formation of these agates are still an ongoing evaluation among geologists. The most agreed upon formation
theory seems to be that the sharp geometric shapes are thought to have been formed in the voids between interlaced crystals of
Barite, or possibly Calcite crystal formations.
The agate nodules can be solid or hollow and the best grades have distinct, colorful fortification agate bands that follow the typically
triangular or trapezoidal shape of the Polyhedroid Agate. They are some of the highest quality agates available, and are able to be
polished to the highest mirror glaze finish that quality agates can obtain. These agates rarely have fractures or other imperfections.
Most nodules are quartz with black, gray, white being the predominant colors of the Polyhedroid agates. Shapes can be a variety of
geometric forms with the equilateral triangle shape being the most desirable shape. (One cannot help but wonder if Euclid, the
father of Geometry found some of these agates or maybe nature made these just to prove Euclid’s theorems.) The Polyhedroid
Agate makes the best agate show piece and conversation piece in any collection. These are very rare and expensive….but like they
say…”You get what you pay for!”  Polyhedroid Agates are our favorites!
We have spent the better part of the last 14 years procuring Polyhedroid
specimens from all over the world. We Have sold a few polished ones from time to
time. As we get older we are realizing that we probably will never be able to cut
and polish all the wonderful Polyhedroid Agates we have collected, so we have
decided to sell off a large portion of what we have collected.

We will be listing here Polyhedroid Agates which are geometrically shaped, mostly
with quartz centers, but can have small agate banding in the center. We will also
be listing some smaller good to AA grade (Jewelry grade) agates. These sell
priced on current market.

When these agates are light colored on the outside, the interior will mostly be
clear quartz. The amount of darkness in the exterior skin will give you an idea of
how much grey or black shading is inside these rare agates. If you look at the
photos above and at our listings you will see the wide array of possibilities for the
interiors of these agates. You never know until you cut one open what surprises
lie hiding inside. We have always been fascinated with Brazilian Agates and we
feel very lucky to have some to offer you for your collection and for you to cut and
polish.

We have also come across a matrix specimen which shows the Polyhedroid agate
formation in crystalline calcite, supporting the current best formation theories. You
can see the calcite blades and agate shapes pointed out with the arrows in the
photo shown on the left. (this specimen has been sold)

This specimen was photographed wet and has had the contrast increased
and has been darkened to better show the polyhedroid agate formations
and calcite plate formations in this face cut matrix specimen from Paraiba
Pentagonal (5 sides) Polyhedroid Agate Rough Nodule from Paraiba Brazil
This is a rough Polyhedroid Agate Nodule that has been cut.  Shown dry, it looks normal. When shown wet, a lavender color is visible.
This may be due to the presence of manganese, while others have suggested that the amethyst color could be from ferric
thiocyanate or sulfur found in amethyst stones. The interior is a botryoidal chalcedony. This is an Exceptionally Rare Polyhedroid
specimen. We have never seen or heard of another specimen like this.
This specimen weighs 2.6 oz or 0.16 lb (74g) and measures 2.4 x 1.2 x 1 inches (62 x 31 x 26mm)
Item # 22PHA04149993
Exceptionally Rare Polyhedroid Agate
Rough Nodule with Quartz and Amethyst
Crystalline Formation

$129.00
Quantity Available 1 each
Polyhedroid Agates in Matrix from Paraiba Brazil
This is the specimen we picked up years ago. It is a piece of the matrix from Paraiba, Brazil. When it was cut, a few
Polyhedroid Agates become visible. The specimen was sealed on the cut face to preserve the integrity of the agate
formation in calcite blade structure. This is the specimen we show at the top of this page.
This specimen weighs 5.7 oz or 0.35 lb (161g) and measures 3 x 1.75 x 1.3 inches (78 x 44 x 35mm)
There is a quadrilateral (almost trapezoidal) agate who's face measures 2.1 x 0.7" (53 x 18mm) and a small kite like
agate that measures 19.5 x 5.9mm easily seen in the photos.
Item # 23PHA04146551
Polyhedroid Agates in Matrix
Photographed Dry
Photographed Wet
Polyhedroid Display Specimen from Paraiba Brazil
This is an Extra Large 1.81 lb "Old Stock" piece from our collection. This was cut and polished in our shop. There is a
nice Triangular Crystalline Face with a small center agate lined vug with drusy quartz crystals inside. This piece shows
the 3 pattern seams in the crystal from the inner triangle vug to the outer skin points. The crystal face also indicates a
possible darker center fill deeper in the agate. This agate has natural angles on the sides which allow for three different
90 degree face displays or about 45 degrees on the back which makes this one a nice natural display specimen. This
could also be cut into slabs  The photos show its different faces and angles.
This specimen weighs 28.9 oz or 1.81 lb (822g)
and measures 4.3 x 3.3 x 3.6 to 1.9 inches (11 x 8.4 x 9.2 to 4.9cm)
Item # 1PHA121605201
Rare Old Stock Polished Face
Polyhedroid Agate Display Specimen

$295.00
We are currently working on cutting some more Polyhedroid
Agates. Some for display and some Jewelry Grade
Polyhedroids. We will be listing them over a six week period in
late February and March of 2018
Cut and Polished in our
Work Shop!
Triangular Polyhedroid Agate Specimen from Paraiba Brazil
This is a Triangular (3 straight sides) Polyhedroid Agate Specimen from our collection. This piece is not polished and is
shown dry. It has a touch of the preferred black inner color and has a botryoidal chalcedony lined center
This specimen weighs 9.78 oz or 0.61 lb (277g) and measures 3.9 x 2.9 x 1.8 inches (9.9 x 7.5 x 4.5cm)
Item # 1PHAS02187412
Triangular Polyhedroid Agate Specimen
(Not Polished)

$58.17
Triangular Polyhedroid Agate Specimen from Paraiba Brazil
This is a Triangular (3 straight sides) Polyhedroid Agate Specimen from our
collection. This piece is not polished and is shown dry. This amazing piece has
clear crackle appearance quartz with a black-grey band in the center of the quartz
band. The interior vug chalcedony forms to a stunning botryoidal interior.

This specimen weighs 1.76 oz (50g)
and measures 3.5 x 2.5 x 0.26 inches (89 x 64 x 6.7mm)
Item # 2PHAS02188830
Triangular Polyhedroid Agate Slab (Not Polished)

$35.00
Triangular Polyhedroid Agate Specimen from Paraiba Brazil
This is a Triangular (3 straight sides) Polyhedroid Agate Specimen from our
collection. This piece is not polished and is shown dry. This amazing piece has
clear crackle appearance quartz with a black-grey band in the center of the quartz
band. The interior vug chalcedony forms to a stunning botryoidal interior.

This specimen weighs 1.62 oz (46g)
and measures 3.2 x 2.4 x 0.26 inches (81 x 61 x 6.6mm)
Item # 3PHAS02187530
Triangular Polyhedroid Agate Slab (Not Polished)

$35.00
Triangular Polyhedroid Agate Specimen from Paraiba Brazil
This is a Triangular (3 straight sides) Polyhedroid Agate Specimen from our
collection. This piece is not polished and is shown dry. This amazing piece has
clear crackle appearance quartz with a black-grey band in the center of the quartz
band. The interior vug chalcedony forms to a stunning botryoidal interior.

This specimen weighs 1.3 oz (37g)
and measures 3.1 x 2.2 x 0.23 inches (79 x 57 x 6mm)
Item # 4PHAS02187820
Triangular Polyhedroid Agate Slab (Not Polished)

$35.00
Triangular Polyhedroid Agate Specimen from Paraiba Brazil
This is a Triangular (3 straight sides) Polyhedroid Agate Specimen from our
collection. This piece is not polished and is shown dry. This amazing piece has
clear crackle appearance quartz with a black-grey band in the center of the quartz
band.

This specimen weighs 1.12 oz (32g)
and measures 32.8 x 2.1 x 0.24 inches (71 x 54 x 6.1mm)
Item # 5PHAS02188420
Triangular Polyhedroid Agate Slab (Not Polished)

$30.00
Triangular Polyhedroid Agate Specimen from Paraiba Brazil
This is a Triangular (3 straight sides) Polyhedroid Agate Specimen from our
collection. This piece is not polished and is shown dry. This amazing piece has
clear crackle appearance quartz.

This specimen weighs 28g
and measures 2.7 x 1.9 x 0.23 inches (69 x 49 x 6mm)
Item # 6PHAS02187120
Triangular Polyhedroid Agate Slab (Not Polished)

$26.00
Triangular Polyhedroid Agate Specimen from Paraiba Brazil
This is a Triangular (3 straight sides) Polyhedroid Agate Specimen from our
collection. This piece is not polished and is shown dry. This amazing piece has
clear crackle appearance quartz.

This specimen weighs 24.5g
and measures 2.5 x 1.8 x 0.23 inches (63 x 46 x 6mm)
Item # 7PHAS02180910
Triangular Polyhedroid Agate Slab (Not Polished)

$24.00
Triangular Polyhedroid Agate Specimen from Paraiba Brazil
This is a Triangular (3 straight sides) Polyhedroid Agate Specimen from our
collection. This piece is not polished and is shown dry. This amazing piece has
clear crackle appearance quartz.

This specimen weighs 21.5g
and measures 2.2 x 1.6 x 0.24 inches (58 x 41 x 6.1mm)
Item # 8PHAS02187610
Triangular Polyhedroid Agate Slab (Not Polished)

$21.00
Triangular Polyhedroid Agate Specimen from Paraiba Brazil
This is a Triangular (3 straight sides) Polyhedroid Agate Specimen from our
collection. This piece is not polished and is shown dry. This amazing piece has
clear crackle appearance quartz.

This specimen weighs 15g
and measures 2 x 1.4 x 0.20 inches (52 x 37 x 5.2mm)
Item # 9PHAS02186110
Triangular Polyhedroid Agate Slab (Not Polished)

$18.00
Triangular Polyhedroid Agate Specimen from Paraiba Brazil
This is a Triangular (3 straight sides) Polyhedroid Agate Specimen from our
collection. This piece is not polished and is shown dry. This amazing piece has
clear crackle appearance quartz.

This specimen weighs 12.5g
and measures 1.8 x 1.3 x 0.21 inches (47 x 33 x 5.4mm)
Item # 10PHAS021867900
Triangular Polyhedroid Agate Slab (Not Polished)

$17.00
Triangular Polyhedroid Agate Specimen from Paraiba Brazil
This is a Triangular (3 straight sides) Polyhedroid Agate Specimen from our
collection. This piece is not polished and is shown dry. This amazing piece has
clear crackle appearance quartz.

This specimen weighs 9.5g
and measures 1.6 x 1.1 x 0.20 inches (42 x 30 x 5.2mm)
Item # 11PHAS02184700
Triangular Polyhedroid Agate Slab (Not Polished)

$16.00
Triangular Polyhedroid Agate Specimen from Paraiba Brazil
This is a Triangular (3 straight sides) Polyhedroid Agate Specimen from our
collection. This piece is not polished and is shown dry. This amazing piece has
clear crackle appearance quartz.

This specimen weighs 7.5g
and measures 1.4 x 1 x 0.23 inches (35 x 26 x 5.9mm)
Item # 12PHAS02188500
Triangular Polyhedroid Agate Slab (Not Polished)

$15.00
Polyhedroid Agates Page 2