Petrified wood crystals?
My friend recently found a big piece of petrified wood covered in small translucent crystal's that are smokey black at the tips. I believe they are some type of quartz due to the heat and the forest fires, this would explain the black trapped at the tips. My friend found them by a creek.. we live in Arizona. I need professional help finding out what these are! The Crystal's are about half a centimeter large each, and they are all clustered together. I am wondering if it is possible for quartz to grow on wood? This was found on a very very old tree. This is very strange and I have not seen any crystalized pieces of petrified wood that look like this anywhere on the web! Help would be greatly appreciated.
Yavapai County Arizona geology