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June 16, 2026
The Prineville Show begins June 17 and we are hoping for some new finds. We hope you are all having a great summer! Beth and Jim ------ Have you joined? The Friends of Fossil Forests is a group which encourages research and conservation, and connects professionals and amateurs interested in petrified forests. |
Welcome to Mills Geological quality identified petrified wood and plant fossils from around the globe |
Our Featured Specimen
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Primitive Conifer (Araucaria Family)
Chinle Formation, Triassic North of Winslow, Arizona ** We might have to go so far as to call this specimen bedazzled – because who couldn't love a specimen of Arizona wood with this unusual covering of sparkling quartz crystals? This new find, on a private ranch north of Winslow, was a feature at the Tucson Show this year. The deposit contained the petrified remains of only two trees -- both of them having extraordinary coatings of smoky and white quartz crystals that formed in desiccation cracks and cavities in the original trees which must have been dead and down for a lengthy period of deterioration prior to becoming covered with volcanic ash and subsequently fossilized. The vast number of specimens available for purchased consisted of almost exclusively the quartz crystals with very little of the wood character remaining. Only two full rounds were recovered from the dig. One of the full rounds had already gone to the University of Arizona, Alfie Norville Mineral Museum, in Tucson. The other full round was quite large (9" diameter and 18" long) and priced at $12,500 so we left it with the dealer hoping it might end up being acquired by a different museum. But this piece has even better presentation of wood character and sparkling quartz than did the full rounds. The glittery coatings on this wood proved particularly difficult for us to photograph, but we hope that you get the feel for how much sparkle this extraordinary specimen has to offer. Summer is here. Put this specimen in a sunny window, on your porch or patio or in some good light in your home. You will not be disappointed. This piece has the best combination of wood character and quartz crystals of any of the specimens, even better than the full round that we left with the dealer. The contrast of smoky and white quartz crystals makes for a great display. The piece also offers some other great features including a knot where a small branch was emerging and several spots we interpret as the beginnings of the Polyporites wardii fungal growths. There is some remaining excellent preservation of the Araucaria tracheids - a feature absent in almost all other the specimens the dealer had to offer. In summary, this specimen is quite unique for Arizona Chinle formation wood. Looking back in history, we note that the Petrified Forest National Monument (now National Park) was set aside in 1908 by Teddy Roosevelt to stop the wanton blasting of petrified logs in order to obtain crystals of amethyst and quartz for manufacture into jewelry. So, this specimen also reflects on an historical anecdote, being from the same Chinle Formation but 50 miles to the west of today's National Park! If you strive for aesthetics in your petrified wood collection, along with excellent provenance, this is a fine candidate to acquire. 4.25" x 2" in cross section; 6.5" in length $595 (… and therefore immediately qualifies for our 10% discount on orders totaling $200 or more) |
Polyporites structure on flat side of specimen
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Pepper tree (Schinoxylon actinoporosum)
Laney Shale Member, Green River Formation, Eocene Blue Forest, Wyoming ** Don't you just love the blue and gray botryoidal agate along the entire length of this limb section? Yes, that is a perfect description of this amazing piece. To make for a perfect display our lapidary cut off a bit of the end and then polished both of the cut faces - limb and end cut. That way it can be displayed numerous ways with always the possibility of showing the cut and polished face. The blue agate is simply among the best we have seen for quite some time and it complements the brown wood perfectly. It takes several photos to show just how covered over with blue agate this beauty is so if you are inclined towards aesthetic specimens, this one is for you; you have found a fantastic new specimen to add to your collection. 2” diameter on each cut and polished face, 3.25" in length limb section, .75" end cut $240 (and therefore immediately qualifies for our 10% discount on order totaling $200 or more) |
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Laurel Family (Laurinoxylon sp.)
Undifferentiated Bridger/Green River Formation; Eocene Oregon Buttes, Wyoming ** There is spectacular anatomical preservation in this specimen! The Lauraceae Family has 45 genera and over 2800 species - a truly bewildering variety within a single family. To make matters worse for wood anatomists, there are large groups of species in which the wood anatomy is nearly identical despite the fact that the reproductive structures (flowers, seeds) are different enough to divide them into species. As a consequence, wood anatomists have erected the taxon Laurinoxylon as a convenient way to simply lump them together into more workable groups (some workers have proposed four different groups but the defining characteristics are not all seen in the transverse plane). This Eocene Wyoming specimen shows some of the main characteristics of Laurinoxylon very nicely. They include somewhat indistinct growth rings, diffuse porous (evenly spaced vessels), vasicentric parenchyma (that is the white ring or glow on the periphery of each vessel), vessel density in the range of 5 to 20 per square millimeter, and vessels both singular and in multiple radial groups of two and occasionally three. The fossil species Laurinoxylon eocenicum has been described in the literature from Yellowstone National Park but there are enough differences that we cannot assign this specimen to the same fossil species. Consequently, we are obligated to use the abbreviation sp. In the Latin name to indicate that a fossil species for this piece is unknown (or more likely, has not been erected in the academic literature). Aside from the interesting anatomy this specimen has absolute "look at me first" qualities for the display cabinet. We absolutely love these pinwheel patterns created by groundwater leaching after the log was petrified. The USGS geologic maps of Oregon Buttes indicate that the Bridger and the Green River Formations do not have a clear point where they can be separated and know we are in one or the other ages. The Green River Formation was quite dependent on ancient Lake Gosiute for sediment collection but after it filled and dried up, the (therefore younger) Bridger Formation continued sediment buildup from the same sources but over a much wider area. A really great display specimen with a story to tell from an interesting area - that pretty much puts a check mark in all the right boxes. 4.25" x 3.75" on polished face; slab 3/8" thick $85 |
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Conifer limb (Pinales Order)
Trout Creek Formation, Miocene Disaster Peak Road west of McDermitt, Oregon/Nevada border ** Full round limb section of coniferous wood. Conifers are not rare at any of the McDermitt collecting spots but neither are they at all common. So, when we see conifers out of an old collection like this one, we tend to simply grab them! This piece has excellent wood grain character along the length of its exterior - the polished face also draws the viewer in for a closer look with its interesting pattern. There are quite a few different sites along the Disaster Peak Road going west out of the village of McDermitt itself. So many in fact that we have to admit to not having visited all of them (in truth, some have been totally depleted over the years and no amount of digging produces anything worthwhile). All that to say we are uncertain of the precise dig at McDermitt which produced this piece. But we are certain that it was likely the fact that it is a conifer that encouraged the previous collector to add it to their collection, as should you! 2.5" x 1.5" on the polished face; limb section 4.5" long $30 |
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Conifer (Pinales Order)
Miocene Cady Mountains, San Bernardino County, California ** An end cut from a single find of petrified wood – very likely the only one that was found in the southern Cady Mountains in several decades. Talk about a vanishing resource. Well, there never really was much found over the many hundreds of square miles that constitute the Collectors’ Cady’s (as they are often called by Southern California Rockhounds). Indeed, this area has mainly been known for marvelous agate and jasper collecting in the past. NO more though. It was included in the new Mojave Trails National Monument and collecting will be prohibited if this National Monument is managed the same way as its sister area to the east, Mojave National Preserve. This significant find was rare before the designation of the new Monument – it will be irreplaceable in the future. This specimen comes out of an old collection. We think it is exceptional. If you can find a better one for sale anywhere – BUY IT! Otherwise, give serious consideration to adding this piece to your collection! 5" x 2" on polished face; end cut varies from 1.5” to 3” thick $69 |
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Black Locust (Robinia zirkelii) Tertiary Denio, Nevada ** A real beauty! Petrified wood from Denio (called "Denio Wood" by collectors and dealers in the last quarter of the 20th century) has become almost impossible to find on the market. The only times it appears seems are when old collections are being sold and that is exactly how this specimen was obtained - it is out of an older collection from which we were privileged to acquire a few choice specimens. The wood from this locality was very distinctive - generally black and white if sanded and polished along the exterior, usually with some orange/yellow/creamy white highlights on the polished face and usually with excellent preservation of woody structure. Most of the limbs were sanded on the exterior of the limb to remove the volcanic ash and enhance the beauty even further. What is NOT distinctive is the locality. And, for good reason. There are two place names called Denio in Nevada which are located well over 100 miles apart. One is the village of Denio on the Oregon border at Nevada State Highway 292. The other one is Denio Camp Springs, now called a "ghost town" with little remaining in the way of buildings but still it can be found on maps just off of Nevada State Highway 34 midway between Vya and Garlock. It was never actually a town; it is the remains of a cabin on land homesteaded by Billie Denio. Personally, I have searched unsuccessfully for the "Denio Wood" locality near both of these geographically named areas. I have talked with different people who were certain they knew the location - the tally included an equal number who KNEW it was near the village of Denio and those who KNEW it was near the Denio Camp Springs. It is noteworthy that none of the folks who KNEW the location had ever actually been there. The vast bulk of Denio Wood was dug by a dealer named Jeff Emmons in either the late 1970s or early 1980s. While I never met the gentleman, I did meet his son at Quartzsite in the early 1980s. He was one of the people who told me it was near the village of Denio but I followed his directions EXACTLY and they were completely inaccurate. He passed away soon after I met him so I was never able to clarify his directions. This limb is a Black Locust. The Latin name Robinia zirkelii is applied to all fossil Robinia in North America. Every collection of petrified wood should have one of these – and here is your chance. 1.5” diameter on polished face; limb section 4” long $85 |
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Primitive conifer (Araucarioxylon)
Chinle Formation, Triassic
Circle Cliffs, County, Utah
** Terrific genuine old-timer here. We recently acquired specimens out of an old collection on which the collector had noted the exact location and year that the piece was collected. Circle Cliffs petrified wood is distinctive for the rich reds and rust-reds that contrast strongly with the blacks, browns and whites. That’s why we love this small slice - it has exceptional presence and is made-to-order for the collector with limited space to store and display their collection. (And maybe we all fall into that category …?) The Araucariaceae Family dominated the Mesozoic Forests.
In the case of the Chinle Formation, the forest was located in the subtropical latitudes with a mild climate and year-round precipitation. That is the reason you see so few specimens with annual growth rings. Like the tropical and subtropical species today, those giant trees just kept growing and did not stop to rest (and thereby develop a growth ring). In the 220 million years that have passed since this tree was alive and well, the entire North American continent, including all of the Chinle Formation, has migrated well north through the process now known as plate tectonics. If you value bulletproof provenance specimens coming out of old collections (like we do here at Mills Geological), this is a perfect fit for your collection.
2.75” x 1.75" on polished face; 1/4” thick slab $29
Chinle Formation, Triassic
Circle Cliffs, County, Utah
** Terrific genuine old-timer here. We recently acquired specimens out of an old collection on which the collector had noted the exact location and year that the piece was collected. Circle Cliffs petrified wood is distinctive for the rich reds and rust-reds that contrast strongly with the blacks, browns and whites. That’s why we love this small slice - it has exceptional presence and is made-to-order for the collector with limited space to store and display their collection. (And maybe we all fall into that category …?) The Araucariaceae Family dominated the Mesozoic Forests.
In the case of the Chinle Formation, the forest was located in the subtropical latitudes with a mild climate and year-round precipitation. That is the reason you see so few specimens with annual growth rings. Like the tropical and subtropical species today, those giant trees just kept growing and did not stop to rest (and thereby develop a growth ring). In the 220 million years that have passed since this tree was alive and well, the entire North American continent, including all of the Chinle Formation, has migrated well north through the process now known as plate tectonics. If you value bulletproof provenance specimens coming out of old collections (like we do here at Mills Geological), this is a perfect fit for your collection.
2.75” x 1.75" on polished face; 1/4” thick slab $29