JH18310 Fluorescent Polyhedroid Agate, Paraiba, Brazil

Description

Up for bid is a great example of the rare and mysterious Polyhedroid Agate from Brazil! This is a nice thick end cut piece that allows you to appreciate the unique geometry from all angles. The cut and polished surface has layers that fluoresces Green, Dark Green and Cream under SW UV and White, Cream and Grey under LW.
The mystery starts with how these Polyhedroid shapes were formed. These can’t be pseudomorphs since their shapes are to variable and don’t match any known mineral. One theory is the sharp geometric shapes were formed in the voids between interlaced crystals of Barite or possibly Calcite but again the angles don’t match up. One clue is the triangular-shaped growth hillocks on their surface and the resulting shapes are consistent with the filling of spaces between intersecting blades of calcite called a ‘box work’ that later dissolved away.
The next mystery is where these came from. Everyone agrees they were first found in 1974 and came from only one specific location in the Paraiba state in northeastern Brazil. However no one is sure exactly where. One story is they came from Sítio Garguelo ("Garguelo farm") in Cachoeira dos Índios. Another story is they came a locality in the storage basin of a new dam. When the dam was filled the location became inaccessible. This explains why no new material has been available for many decades.
The original piece of rough was about 5” wide, 2” high and 3” long and was cut in two. This yielded two nice large specimens. Other half is being sold as a separate auction. Most of the Polyhedroid rough is completely cut up into thin slabs so it is rare to find a large specimen like this. Back of the specimen was broken off but hole was mostly closed with a soft brown material.
Description: Polyhedroid Agate (FL Green, Cream, Dark Green, SW, White, Cream, Grey LW)
Location: Paraiba, Brazil
Size: 4.4" x 2" x 1.9"
Weight: 6.9 oz
Contact me if you have any questions. Be sure to check out my eBay store:
Jim's Obscure Stuff
for more fluorescent minerals and other unusual items.
Domestic Shipping
For domestic shipping I generally use Fed Exp Ground for heavier and more expensive items, and US Postal Service Priority Mail for lighter and less expensive items. Both services have door to door tracking and full insurance. If you have a shipping preference please let me know. If the shipping service I use costs less than eBay charges, I will refund any excess. I only charge actual shipping costs with no extra charges for packing or shipping materials and will gladly combine shipments. If the combined shipping doesn’t work for some reason, I will refund any excess shipping.
International Shipping
I use US Postal Service Priority mail for all international shipments. Please note that due to a lack of international flights, many overseas shipments are going by boat instead of air. This can add a month or more to delivery times. Purchase at your own risk.