Grey dendrites!

This petrified wood shows a mix of brown, orange, and some white crystalline inclusions. The patterns and colors suggest it might be from a region known for such mineralization. Here are a few possibilities:

Arizona Petrified Wood: This type often features vibrant colors with intricate patterns due to iron oxides and other minerals.
Oregon Petrified Wood: Known for its colorful specimens with similar patterns, often due to the presence of silica and other minerals.
Washington Petrified Wood: This can also display similar characteristics, with unique patterns due to the geological processes in the area.

The white crystalline inclusions could be quartz or calcite, which are common in petrified wood.