14.5" Agate/Mineral Replaced Petrified Wood - Tom Minor Basin, Montana

This is a 14.5" wide slab of a petrified wood cast from the Tom Miner Basin area of Montana. While not technically petrified wood, it's created when the the organic material is destroyed and the void is filled in with silica (agate) and other minerals. The slab has been polished to a glossy finish on one side and comes out of an old collection.

This piece is exceptionally beautiful when backlit as it's transparent in spots and the many layers present from multiple deposition events can be seen. There are repaired cracks through this specimen. Comes with a display stand.

Petrified wood is the name given to wood that has been turned into stone (fossilized) through the process of permineralization. All of the organic matter becomes replaced by minerals, while much of the original structure such as tree rings in retained. For this to happen the wood needs to be buried in an environment both low in oxygen (preventing decomposition) and with flowing, mineral-laden water. The coloration is due to the various minerals that are present during fossilization. For example red colors are due to iron compounds, greens due to copper, etc.

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.
Tom Miner Basin, Montana
14.5" wide, 11.7" tall, 1" thick
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