This pitch black, cut and polished piece of Petrified Wood was found in the Kaipara Harbour on the North Island of New Zealand more than 20 years ago.
Pitch black pieces like these were very rarely found by "Rockhounds" back in the day when they used to struggle through the thick mud at low tide with sticks & rods, prodding the mud, hoping to hit something solid, sometimes more than a meter down under the mud...
Petrified wood (from the Greek root petro meaning "rock" or "stone"; literally "wood turned into stone") is the name given to a special type of fossilized remains of terrestrial vegetation.
It is the result of a tree or tree-like plants having completely transitioned to stone by the process of permineralization. All the organic materials have been replaced with minerals (mostly a silicate, such as quartz), while retaining the original structure of the stem tissue.
Unlike other types of fossils which are typically impressions or compression's, petrified wood is a three-dimensional representation of the original organic material. The petrifaction process occurs underground, when wood becomes buried under sediment and is initially preserved due to a lack of oxygen which inhibits aerobic decomposition.