This is a polished slab featuring a band of quartz crystal surrounding agate bands in dark blue, translucent, yellow, and white with a crystal center.

17.1 cm x 11.6 cm, 6 mm thick
6.0 oz

Polyhedroid Agates were found in Paraiba, Brazil, but are now unavailable. They are pseudomorphic formation of agate, forming in the negative space between large crystals of calcite or aragonite. They uniquely feature naturally flat surfaces in a variety of angles.

https://thegemshop.com/products/pol112jr-polyhedroid-agate-slab