Petrified Wood. ID help and discussion.

[NicolaiT13]

Over the past couple weeks I have seemed to find multiple variations of petrified wood. In this picture the top few pieces were all found in the same area and some of the smaller pieces that I found have little crystals throughout them (like the one in the top of this image). The piece I found on the bottom confuses me because it resembles wood but also has a mineral/rock look to it. I have read into agatized petrified wood but I still don't know much about that process. In the past I have found very large pieces of what I believed to be petrified wood but the majority of the piece resembled a crystal. Unfortunately I don't have those with me but will post a picture of them when I get home. Any info and help on the subject would be appreciated. Also sorry the picture posted weird. When i refer to the top I mean the right side of the image. Thanks, Nic 

[NicolaiT13]

Here is a picture of the bottom side of the last piece I discussed. 

[ynot]

Hey Nicola,

There are many minerals that will replace wood to make petrified wood.

It is very common for agatized wood to have small quartz crystals in it.

There are also several ways that the wood can be replaced.

There can be a complete cast where the wood was gone before the cavity was filled with mineral, leaving the exterior appearance only. Then on the other extreme, the wood can have its cellular structures preserved. This type of preservation is on the scale of one molecule at a time.

To identify to genus/species You need to look at the cellular structures and how they are distributed through the wood.

[GeschWhat]

Are these from the Hell Creek Formation? I was on a dig last summer up near Marmarth, ND. The dirt road we had to drive to access the site was paved with these - and I ended up with one stuck in my tire. 

[NicolaiT13]

Yes I found these in the Hell Creek Formation. Fairly close to Marmarth actually.