5" Polished Banded Agate with Wegeler Effect - Aouli, Morocco

This is a gorgeous polished agate nodule half that was collected from Aouli, Morocco. The tightly packed, alternating translucent to opaque banding of this agate results in this specimen exhibiting a Wegeler effect when rotated.

It has been cut flat and polished to a glossy finish along the flat cut, and is accompanied by an acrylic display stand.

The wegeler effect, also known as the shadow effect or parallax effect, is a three-dimensional oddity in which rotating the agate results in the appearance of lines that move. One line will move with the source of light while the other moves with your point of view. This occurs in agate that has tightly packed, alternating bright opaque bands and transparent bands.

Agate is a variety of microcrystalline quartz (chalcedony) that displays translucence and in some cases banding. Agate primarily forms when silica-rich fluids fill pockets within rock and/or fossils, resulting in deposition of the silica along the walls of the rock. This process can result in banding patterns as the composition and impurities of the fluids change over time. These banding patterns can either form as flat layers or rounded layers, depending on the surfaces available for deposition.

Chalcedony var. Agate
Aouli, Morocco
5 x 2.5", up to 1.6" thick