Polyhedroid Agates Page 1
Courtesy Ben Edwards Collection
Courtesy 2009 Gem Shop Calendar
Polyhedroid Agates Page 1...these 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 right triangle or the equilateral triangle shape being the most desirable shapes.
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 30 years collecting Polyhedroid Agate specimens. We sell a few polished , cut or rough 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 few of what we have collected.
This rare 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 photo lends some insight into how some of these legendary polyhedroids are formed.
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 all will sell based on current market pricing.
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 but especially so with these Rare Polyhedroid Agates. We feel very lucky to have some to offer you for your collection and maybe even some for you to cut and polish.
Item # 51PHA11182900
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
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 rim of the preferred black inner color and has a botryoidal chalcedony lined center
This specimen weighs 1.34 oz (37.5g) and measures 3.5 x 0.9 x 0.89 inches (89 x 23 x 22mm)
Item # 52PHA11185110
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Sequential cut Pair of Triangular Polyhedroid Agate Rough Slabs from Paraiba Brazil
This is a rough cut pair of Polyhedroid Agate slabs of jewelry grade suitable for making a pair of earrings. Shown dry. These slabs were cut one after the other in sequence and are as close to possible of being a matched pair These are an Exceptionally Rare Polyhedroid specimen pair which show an excellent pattern when back-lit or when polished.
These specimens weigh 1g and measures 25 x 12.4 x 2.9mm and 1.5g and measures 26.7 x 14.1 x 2.9mm
Item # 54PHA11182810
Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab
$30.00
Quantity Available 1pair
Triangular Polyhedroid Agate Rough Slab from Paraiba Brazil
This is a rough cut Polyhedroid Agate slab of jewelry grade suitable for making a pendant or a brooch. Shown dry. This slab is an Exceptionally Rare Polyhedroid specimen which shows an excellent pattern when back-lit or when polished..
This specimens weighs 4g and measures 36.4 x 18 x 4.6mm
Item # 55PHA11189310
Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab
Triangular Polyhedroid Agate Rough Slab from Paraiba Brazil
This is a rough cut Polyhedroid Agate slab of jewelry grade suitable for making a pendant or a brooch. Shown dry. This slab is an Exceptionally Rare Polyhedroid specimen which shows an excellent pattern when back-lit or when polished..
This specimens weighs 3g and measures 39.6 x 19.9 x 2.9mm
Item # 1PHA121605201
Rare Old Stock Polished Face Polyhedroid Agate Display Specimen
$595.00
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 # 2PHAS0218S3000
Triangular Polyhedroid Agate Slab (Not Polished)
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 # 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 9.5g and measures 1.6 x 1.1 x 0.20 inches (42 x 30 x 5.2mm)
Item # 12PHAS02188500
Triangular Polyhedroid Agate Slab (Not Polished)
$15.00
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 # 23PHA04146551
Polyhedroid Agates in Matrix
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.