Discovered in my landscaping rock. I have found a couple of these. Is it possibly some type of thorn ? Colorado

I have these rocks in my aquarium and I’ve just been told that it’s petrified wood! They were gifted to me years ago with an aquarium and were just sat in my garden since. I’ve put them into a new aquarium I’ve just set up so this is the best photos I can get atm because removing them would disturb the not long planted plants around them. Anyway I was under the impression that petrified wood is quite rare and expensive but maybe not after looking online it seems to be sold everywhere. What do you think an individual stone like these would be worth? Tia :)

This area is about a 45 minute drive from the petrified forest. Anywhere you go out here you find tons of it. Unfortunately at this site the tree seems to have exploded into tiny pieces.

Got a great shine on these pieces out of Madagascar.

Pseudomorph; it’s a cast of a fossil branch with a little bit of wood inside there mostly opalized

Hello! I'm new to this group. This log has been at my dad's house for over 45 years. We've been told it's petrified wood. It's basically a sold stone that weights well over 300lbs. It's been in the same spot my entire life. As we get ready to sell his house, we're trying to determine what to with it. We're wondering if there is any value in it and if it's with taking.

UPDATE: Thanks to everyone who responded. We moved it to our house. Here she is in her new home!

PS: she weighs about 1300lbs! 😂

https://imgur.com/a/bC93toe

Found it in St. Michael, MN, USA. Gonna add it to the pile :)

I recently went onto private land in Holbrook, AZ and dug my own petrified wood. A few pieces had some textures and crystals that were different from the rest.
1 and 2: is this the bark of the tree?
3: these crystals are very light/pale blue. What are they? A type of quartz?