7.5" Petrified Wood (Araucarioxylon) with Fungus Rot - Arizona

This is a stunning, 7.5" wide polished section of Late Triassic petrified wood (Araucarioxylon) from Navajo County, Arizona. It has been cut flat and polished on one face and one edge has been cut flat for presenation. The petrified wood contains fossilized fungus (the circular formations). This parasitic fungus grew on the tree while it was still alive and has been named Polyporites wardii. There is also an unidentified blue mineral between some of the brecciated wood fragments.

The vibrant coloration is due to the contaminating minerals in the silica which replaced the original wood structure. For example pinks and reds are due to hematite, a form of oxidized iron. This is similar to petrified wood which is found in the Petrified Forest National Park. The petrified forest encompasses nearly 100k acres and this wood comes from land outside of the park.

The petrified wood from the extinct conifer Araucarioxylon arizonicum which happens to be the state fossil of Arizona. The petrified wood of this tree is frequently referred to as "Rainbow wood" because of the large variety of colors some specimens exhibit. The reds and oranges come from hematite inclusions within the silica, the yellows from limonite and the purples from magnesium based minerals.

Araucarioxylon arizonicum is estimated to have grown more than 150 feet high and dominated the tropical forests in what is now Arizona nearly 225 million years ago.
Araucarioxylon arizonicum & Polyporites wardii (Fungus)
Navajo County, Arizona
Chinle Formation
7.5 x 7", up to 2.2" thick
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