Coloring by Brody Dymond

Coloring by Hunter Maeder

Coloring by Hunter Maeder

Prehistoric Life by Hunter Maeder

 

Unlocking the Secrets of Anyolite!

By Broden Dymond

Have you ever seen a rock that looks like it has a ruby hidden inside it? If you have, you might have seen anyolite! Anyolite is a metamorphic rock made up of three different minerals: zoisite, ruby, and sometimes amphibole. It is also known by its trade name, “ruby in zoisite.”

Figure 1. Anyolite from Mundarara Mine, Tanzania. Red colored ruby inclusions are visible. Specimen on display at the Idaho Museum of Natural History, Pocatello, Idaho. Photo source Wikimedia Commons.

The Discovery and Trade of Anyolite

Anyolite was first discovered in 1954 in Longido, in northeastern Tanzania. The mine where it was first discovered is still in use today, and anyolite is still exported from Tanzania.

Anyolite is also used in artwork and decorative items. It can be made into sculptures, figurines, ornamental objects, and jewelry designs. Some people also use it in meditation practices because they believe it can help relieve stress and support emotional healing.

But be careful! There is a similar-looking mineral called ruby in fuchsite that can be confused with anyolite. One way to tell them apart is with a hardness test. Fuchsite has a hardness of only 2–3.

The Geology of Anyolite

Anyolite is a metamorphic rock, and it usually has a Mohs hardness of 6–6.5. It contains three minerals that give it an interesting appearance.

The first mineral is zoisite. Zoisite contains chromium, which causes its vibrant green color.

The second mineral is ruby. Ruby is made of corundum crystals, which are a crystalline form of aluminum oxide. The ruby is what makes anyolite especially interesting because the bright red ruby crystals stand out against the green zoisite.

The third mineral is amphibole. Sometimes you can see black specks in anyolite that are made of a type of amphibole called hornblende tschermakite.

Figure 2. Anyolite from Tanzania, Africa. Note rubies. Photo by Hannes Grobe Creative Commons CC-BY-SA-2.5.

The Fluorescence of Anyolite

The cool thing about anyolite is that the ruby in the rock actually glows!

When you hold a UV light to anyolite, the ruby glows. This makes anyolite even more interesting because you can see something happening inside the rock that you normally wouldn't be able to see.

Figure 3. View of anyolite. From the collection of B. Dymond. Photo by B. Dymond.

Figure 4. View of anyolite fluorescing under a UV light. From the collection of B. Dymond. Photo by B. Dymond.

So, the next time you see a green rock with red spots, take a closer look. You might just be looking at anyolite!

About the author

BRODY DYMOND is a member of the Grand Traverse Area Rock and Mineral Club’s Pebble Pups in Traverse City, Michigan. He is from Glen Arbor, Michigan, where he lives. Brody is thirteen years old and will be starting 7th grade at Glen Lake School this year. He has been involved with Pebble Pups for over four years. He has a keen interest in rocks and fossils, and also enjoys being outdoors, biking on trails, robotics, engineering, art, gaming, and Legos. He is currently a Scout from Troop 131 in Suttons Bay, Michigan. He is a program assistant with the Pebble Pup program.

Studying A Fossilized Fern

 By Wyatt Maeder

The fossilized fern pictured in this paper (Figure 1) was found in the famous Mazon Creek fossil beds near Morris in Grundy County, Illinois. Paleontologists have identified this specific specimen as Ptychocarpus unitus. These renowned fossil beds have been actively studied since the middle of the nineteenth century.

Together, the matrix and fossil weigh 14 grams (0.5 ounces). The fossil and its surrounding matrix measure 3 centimeters (1.2 inches) in length. The fossil itself is 1 centimeter (0.4 inches) wide, while the matrix is slightly over 2 centimeters (0.8 inches) wide. This specimen is estimated to have formed during the mid-Pennsylvanian, roughly 309 million years ago.

Figure 1. Ptychocarpus unitus is an extinct fossil fern from the Pennsylvanian Period, preserved in the Mazon Creek Fossil Beds Photo date 2026 by Wyatt Maeder.

As you can see in figure 1 the fern fossil and matrix are a reddish-brown color. This means it is preserved in an ironstone concretion. Some studies show that there could be traces of organic carbon. I do not know this because I don’t have access to a gas spectrometer. 

 

Table. 1 Identification
Taxon:	Ptychocarpus unitus
Family:	Marattiaceae
Locality:	Mazon Creek, IL
Time Period:
Era	Paleozoic
Period	Middle Pennsylvanian

Thanks to exceptional preservation like that found in this fern, scientists can reconstruct ancient equatorial ecosystems, helping us learn more about late Paleozoic plant life, climate, and evolutionary history.

References

Hoskins, J. H. (1933). A Ptychocarpus Type of Fructification from Illinois. The American Midland Naturalist, 14(6), 726–728. https://doi.org/10.2307/2420131

Jennings, J. R., & Millay, M. A. (1979). Morphology of the fertile Pecopteris unita from the Middle Pennsylvanian of Illinois. Palaeontographica Abteilung B, 170(1-3), 51–65.

Tripp, M., Schwark, L., Brocks, J. J., Mayer, P., Whiteside, H. J., Rickard, W., Greenwood, P. F., & Grice, K. (2023). Rapid encapsulation of true ferns and arborane/fernane compounds fossilized in siderite concretions supports analytical distinction of plant fossils. Scientific Reports, 13(1), Article 19851. https://doi.org/10.1038/s41598-023-47009-8

About the author: Wyatt Maeder is a member of the Grand Traverse Area Rock and Mineral Club’s pebble pups. He is 11 years old and in 6th grade.

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Pebble Pup Dinosaur Artwork

 

Hunter Maeder is in second grade and is 8 years old.

Investigating an Ancient Roman Architectural Artifact

 By: Wyatt Maeder, Pebble Pup

This Roman tile fragment was found in the Roman Empire. The exact location is unknown. The tile may have covered a Roman home or business. It looks like a type of tile called a Tegula, a flat rectangular tile with raised flanges on the sides. The analysis of the artifact is in the following table.

Artifact Analysis: Roman Ceramic Tile
Probable origin	Roman
Estimated age	Circa 1,926 years old (100 CE)
Classification	Tegula (flat roof tile) with a raised flange on its side
Physical Dimensions
Weight	0.54 kilograms (1 lb. 3.1 oz)
Length	14 cm (5½ in)
Width	11 cm (4¼ in)

Composition & Mineralogy

Visual inspection suggests a fabric rich in quartz grains and iron oxide, which gives the ceramic its characteristic hue. The presence of dolomite is also suspected, likely introduced via sand temper. 

The tile may also contain natural clay from the Moza Formation, however, to determine this it would require laboratory analysis. Without a kiln-site test, it remains unclear if the material is refined clay from Rome or the Levant (Roman Judea). If is from Rome, it would likely be made from volcanic clays or muddy deposits from the Tiber Valley. Clays from around Rome are heavily influenced by the volcanic history of the Lazio region. Under a microscope, you would expect to see volcanic minerals such as augite (pyroxene), biotite, and sanidine (feldspar). Some Roman bricks even contain tiny fragments of volcanic tuff.  If it is from the sedimentary Moza Formation there would be dolomitic sand and you would see dolomite crystals and limestone fragments, but you would find zero volcanic minerals like pyroxene. Moza Clay typically fires to a light pinkish-orange, yellow-brown, or buff color. Because it is often rich in calcium carbonate (marl), it has a "creamy" look when fired at standard temperatures. Roman (Tiber) Clay: Often has a deeper red to reddish-brown hue due to the specific iron oxides found in the volcanic-rich Italian soils.

Figure 1. Side view of a fragment of a Roman tile, likely a roofing (tegula) tile. Photo date 2026 by W. Maeder. From the collection of Wyatt Maeder.

Figure 2. View of the top of the Roman tile. Note the red coloration and thickness of the tile. Photo date 2026 by W. Maeder. From the collection of Wyatt Maeder.

Manufacturing Process

Making a Roman roof tile was a lot like a professional version of making a clay project in a classroom, just on a much larger scale. First the workers dug up natural clay and mixed it with water. They added a little sand or crushed old bricks (called "temper") to keep the tile from shrinking or cracking when it got hot. Then the workers shaped the tile, they pushed the wet clay into a wooden frame, sort of like a large brownie pan. For a flat roof tile (tegula), they would use their fingers to create raised edges (flanges) on the sides so the tiles could lock together (see figure 1. and 3). Next it was time to stamp and dry the tile. While the clay was still soft, the workshop would often press a stamp into it—like a brand name—to show who made it. Then, they left the tiles out in the sun to dry out most of the water. Next, it is time to fire the kiln: The dry tiles were stacked inside a massive brick oven called a kiln. A fire was kept burning underneath for several days. Once the temperature hit around 900°C, the clay turned into hard, waterproof stone-like tile. Finally, after the kiln cooled down, the tiles were ready to be shipped to a construction site to keep a Roman house dry for hundreds of years.

Figure 3. Closeup of tile showing a raised flange on a Roman tile. Photo date 2026 by W. Maeder. From the collection of Wyatt Maeder.

Whether used as a protective roof covering or a component of a heating system, this artifact serves as a remarkable testament to the intersection of ancient mineralogy and ritualistic craftsmanship. Its enduring composition highlights the sophisticated engineering techniques that have allowed Roman architectural elements to survive for over a millennium.

Acknowledgment: Special thanks to my Mom for all the hard work she did to help me with this paper. Steven Veatch provided critical review. 

Reference and further reading:

Brodribb, G. (1987). Roman brick and tile: An analytical survey and corpus of surviving examples.

Cohen-Weinberger, A., Levi, D., & Beʾeri, R. (2020). On the raw materials in the ceramic workshops of Jerusalem, before and after 70 C.E. BASOR: Bulletin of the American Schools of Oriental Research, 383(1), 33–59. doi.org

Cohen-Weinberger, A., Martin, M., & Goren, Y. (2024, February 11). Israel-Palestinian Authority/central highlands/Moza clay. The Levantine Ceramics Project. https://www.levantineceramics.org/petrofabrics/32-israel-palestinian-authority-central-highlands-moza-clay.

Gerding, H. (2006). Early use of fired brick in Hellenistic and Roman architecture. In C. Mattusch, A. Donohue, & A. Brauer (Eds.), Common Ground: Archaeology, Art, Science and Humanities - Proceedings of the 16th International Congress of Classical Archaeology, Boston, August 23-26, 2003 (pp. 355-358). Oxbow Books.

A Brachiosaurus by Hunter