(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!

Polyhedroid Agates Page 1

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.

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

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)

Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Item # 51PHA11182900

Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs

$30.00
Quantity Available 1pair

Sold Out!

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)

Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Item # 52PHA11185110

Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs

$30.00
Quantity Available 1pair

Sold Out!

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

We are always looking for Polyhedroid Agates. Some just for display and some Jewelry Grade Polyhedroids. We will be listing them as we are able to locate them.

Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab
Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab
Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab
Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab
Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab
Item # 53PHA11180610

Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab

$30.00
Quantity Available 1pair

Sold Out!

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 3.5g and measures 33.2 x 15.9 x 4.5mm

Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab
Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab
Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab
Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab
Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab
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

Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab
Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab
Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab
Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab
Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab
Item # 55PHA11189310

Exceptionally Rare Jewelry Grade Polyhedroid Agate rough cut slab

$39.00
Quantity Available 1pair

Sold Out!

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

Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs
Item # 50PHA11187970

Exceptionally Rare Jewelry Grade Polyhedroid Agate Pair rough cut slabs

$30.00
Quantity Available 1pair

Sold Out!

Sequential cut Pair of Pentagon Polyhedroid Agate Rough Slabs from Paraiba Brazil

This is a rough cut pair of Polyhedroid Agate slabs of jewelry grade suitable for making pendants or necklaces. 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 9g and measures 44 x 30.2 x 4.5mm and 8.5g and measures 44.2 x 29.5 x 4.5mm

Rare Old Stock Polished Face Polyhedroid Agate Display Specimen
Rare Old Stock Polished Face Polyhedroid Agate Display Specimen
Rare Old Stock Polished Face Polyhedroid Agate Display Specimen
Rare Old Stock Polished Face Polyhedroid Agate Display Specimen
Rare Old Stock Polished Face Polyhedroid Agate Display Specimen
Rare Old Stock Polished Face Polyhedroid Agate Display Specimen
Rare Old Stock Polished Face Polyhedroid Agate Display Specimen
Rare Old Stock Polished Face Polyhedroid Agate Display Specimen
Rare Old Stock Polished Face Polyhedroid Agate Display Specimen
Rare Old Stock Polished Face Polyhedroid Agate Display Specimen Rare Old Stock Polished Face Polyhedroid Agate Display Specimen Rare Old Stock Polished Face Polyhedroid Agate Display Specimen Rare Old Stock Polished Face Polyhedroid Agate Display Specimen Rare Old Stock Polished Face Polyhedroid Agate Display Specimen Rare Old Stock Polished Face Polyhedroid Agate Display Specimen Rare Old Stock Polished Face Polyhedroid Agate Display Specimen Rare Old Stock Polished Face Polyhedroid Agate Display Specimen Rare Old Stock Polished Face Polyhedroid Agate Display Specimen
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)

Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished)
Item # 2PHAS02188830

Triangular Polyhedroid Agate Slab (Not Polished)

$35.00

Sold Out!

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)

Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished)
Item # 3PHAS02187530

Triangular Polyhedroid Agate Slab (Not Polished)

$35.00

Sold Out!

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)

Polyhedroid_Agate_4_6_
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Polyhedroid_Agate_4_6_ Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished)
Item # 4PHAS02187820

Triangular Polyhedroid Agate Slab (Not Polished)

$35.00

Sold Out!

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)

Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished)
Item # 5PHAS02188420

Triangular Polyhedroid Agate Slab (Not Polished)

$30.00

Sold Out!

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)

Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished)
Item # 10PHAS021867900

Triangular Polyhedroid Agate Slab (Not Polished)

$17.00

Sold Out!

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)

Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished)
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)

Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished)
Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished) Triangular Polyhedroid Agate Slab (Not Polished)
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)

Polyhedroid Agates in Matrix
Polyhedroid Agates in Matrix
Polyhedroid Agates in Matrix
Polyhedroid Agates in Matrix
Polyhedroid Agates in Matrix
Polyhedroid Agates in Matrix
Polyhedroid Agates in Matrix Polyhedroid Agates in Matrix Polyhedroid Agates in Matrix Polyhedroid Agates in Matrix Polyhedroid Agates in Matrix Polyhedroid Agates in Matrix
Item # 23PHA04146551

Polyhedroid Agates in Matrix

Sold Out!

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.