If you're new to my store, you don't know my story about how I ended up with piles of rocks that you just can't find "in the wild" anymore. Here's the really short version:
My dad was a great rockhound who hunted the most productive agate and jasper fields in the West starting around three-quarters of century ago. He accumulated a lot of great rocks, but he's not around anymore. I've got all those rocks now. If you want to know more, read the other blog posts here or leave me a message.
One of the most prized rocks found in the West is called "Yellow Cat Wood". It was once found (but no more) in the Yellow Cat/Poison Springs area north of Arches National Park in Utah. There are documented cases where chunks of Yellow Cat have sold at auction for prices in five figures. The "high end" rare rock auction house, FossilEra.com, contained this comment in December 2022:
"A large limb section of this gem quality wood recently sold for over $50k in auction."
Since my dad was one of the early rockhounds, he collected some genuine Yellow Cat. This is classic Yellow Cat from his collection and there is no doubt about it.
As I sift through the piles of rocks I have now, I have started to find rocks that might, or might not, be genuine Yellow Cat wood. I'm pretty sure that my dad found these rocks himself in the south east Utah desert. I have a small pile of them now. They're quite distinctive and easy to recognize. I'd love to list a few for sale but until I find out what a fair price is for them, I'm not going to do that.
Here's my case:
The colors are the same. The shades of red and yellow in a rock can tell you a lot because the colors are a result of the fundamental geological history of area where the rock was formed. -- The amount and type of iron and other elements in the soil; how much and what kind of silica bearing water resulted in the replacement, and so forth.
My dad did a lot of rockhounding in the Yellow Cat/Poison Springs area. I know this because he took me along on some of the trips when I was a kid.
An authority on rockhounding in that area has written about one of my my dad's closest friends. "Wayne Johnston of Price, Utah (pers. comm., 1999), a cowboy who rode this barren range in the 1930s, tells of looking down from his horse and seeing red wood on the ground." "Colorful Agate and Jasper of Southeastern Utah", Rocks and Minerals, 05 Jun 2014, page 313, Richard D. Dayvault
Both my rock and genuine Yellow Cat wood are always casts. That is, they preserve the shape and surface of whatever created the void that was filled by agate, but not the internal wood structure. Both my rocks and genuine Yellow Cat have very similar exteriors.
I'm VERY reluctant to claim that what I have is actually Yellow Cat wood because that would simply be too self-serving. Dayvault cites an example of Yellow Cat wood going for "thousands" at Heritage auctions. I'm not going to make a claim that these rocks are actually Yellow Cat wood unless I am damn sure.
The biggest reason I'm not ready to claim that the rocks I have been finding recently are Yellow Cat wood is that the interior of these new rocks just doesn't look like it genuine, classic Yellow Cat. There is usually fortification banding in genuine Yellow Cat. That banding is totally absent in these new rocks.
The most distinctive feature of the new rock is the exterior. It's the best way to identify it. I can always find at least one part of the rock that has this distinctive surface. Here's a closeup of that exterior.
Here's a photo of the exterior of my dad's genuine Yellow Cat wood.
Here's another piece of the mystery rock.
Now ... I ask you ... Are these new rocks Yellow Cat?
M. Holden -- Reddit screen ID: Holden3DStudio -- answered the call with an idea that had never occurred to me before. Here's my summary of his idea.
What you're seeing is a piece of bark from a big tree -- maybe like a Sequoia -- that was folded over like a taco and formed a space in the ground where silica could replace the bark -- and the space in the ground. I know that this happened a lot with thundereggs and geodes with only a bubble of volcanic gas to form the space replaced with agate.
Good idea!
This explanation would account for all of the mysteries that have been puzzling me about the rocks.
The lack of any interior structure. Check.
The common exterior surface. Check.
The agate similarity with Yellow Cat wood. Check.
And the "fat pancake" shape that is often seen. Check.
It even explains that "groove" in Figure 5 above.
M. Holden's idea would also account for the lack of any other examples remotely like it. It is entirely possible that this only happened once or maybe just a few times. My dad didn't find much ... just enough to establish a type. And, although I have said that it doesn't have any interior structure, that's not entirely true. The interior is just not like "classic" Yellow Cat wood. But examined closely, it often has much mnore muted plumes and banding.
Yellow Cat Bark ?
By far, the most distinguishing feature of what I am now calling, "Yellow Cat Bark" is the outer surface. The M. Holden suggestion that pushed me over the finish line was that the surface looked just like the bark on trees today. He said I should look at pictures of Sequoia bark to compare them. So I did.
I'm also convinced that the rocks are either completely unique or very rare. Like all of my dad's rocks, I do want to share them with the world. Unlike some of his rocks, my supply is only big enough to share them with a very few people so I'll be pricing these rocks on the "high side" but nowhere near what others would charge. I want whoever gets a piece to be serious about it, but I don't want to price it out of reach. For example, I've sold chunks of my dad's Utah red horn coral for just ten percent of the price of almost identical chunks at other sites, and these days I give away more than I sell. But like the horn coral, I won't be listing it all the time. I plan on taking my time to sell the limited supply I have.
Like my "Mission Statement" states:
"I'm not really in business. I'm just having fun with my dad's rocks."
At Reddit, user "Mamadog5" posted about Yellow Cat wood. Reddit comments don't support pictures so I'm posting these pics from Dayvault's article here.
I will start by saying that your mystery rock is a very nice specimen. It almost looks like a mashup of your Marvy Agate, Utah Grape Agate, and perhaps a little Yellow Cat Wood. I still maintain that it likely does not have a specific name; there is probably not enough quantity nor familiarity to have a widely used name. However, Yellow Cat Wood/Agate is on a whole other level. The colors and fortifications/banding are much more striking and appealing. I think the resemblance in their exteriors has more to do with their similarity in formation, rather than being the same rock. Similar to how agate exteriors from Mexico can look similar to those from Mozambique. That said, both of thes…