This is a phenomenal, 8.2" wide slab of Trent Agate from Oregon. This rare agate contains inclusions of stibnite and red realgar. The slab has been polished to a mirror-like finish and comes with a display stand.
The white bordered photo is a backlit photo of the specimen, explaining the color change between the black and white bordered photos. The depth of the stibnite crystal formations can clearly be seen in this backlit photo.
Trent stibnite agate, also known as "Trent agate", is a very unique and rare agate formation which occurred around crystal sprays of stibnite and/or realgar. Trent agate was collected in the 1960's, from a railroad cut in Trent, Oregon. Following an accident at the site of collection, the mine was closed and eventually covered by a road. Specimens of this beautiful agate are now only obtainable through old collections.
Like many other agates
, Trent agates form by deposition of microscopic silica crystals in concentric layers within cavities of rocks. The colors of the agate are dependent on impurities within the silica-rich solutions, which in this case are a result of the arsenic, realgar and stibnite.