The 250 million-year process that turned this portion of a tree to metal is still not fully understood by geologists.
We have been studying this phenomena and have a publication awaiting review that goes into more depth on how it may have happened.
In the meantime, enjoy this video of a large piece of a tree turned almost entirely to metal – chalcocite (Cu2S), which is almost 70% copper by weight. This specimen was expertly trimmed and cleaned with unprecedented artistry.
Note that the log is sitting on a steel swivel, as lifting the 35 pounds to turn it around would be otherwise quite difficult, and maybe impossible to have left a free hand for the camera. The color is much more vibrant in person, with a lot more depth to the greens and much more blue than comes through in the video. And, yes, this did have to come off the side of the mountain in a backpack!