UW Geology Museum

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Quartz is one of the most simple and common minerals in the Earth’s crust. With such a simple crystal structure and so m...
06/16/2026

Quartz is one of the most simple and common minerals in the Earth’s crust. With such a simple crystal structure and so many environments of formation comes many opportunities for variation! Quartz comes in a gorgeous rainbow of varieties, every one of which has its own appeal.

🔴Hematoid quartz contains hematite inclusions in and on its crystals.
🔶Carnelian is a type of chalcedony with a trace iron oxide component.
⭐Citrine has a trace iron content or aluminum color centers.
🟢Prasiolite contains trace amounts of Fe(2+) compounds.
💠Blue chalcedony is caused by the Tyndall Effect, where light is scattered by colloidal particles.
🔷Dumortierite quartz contains long, thin inclusions of dumortierite.
🟪Amethyst is caused by irradiation and trace Fe(3+) content.
❣️Rose quartz has thin dumortierite inclusions or aluminum and phosphorous color centers.
🟤Tiger’s eye is the intergrowth of quartz crystals with crystals of limonite after amphibole.
⬛️Smoky quartz contains aluminum color centers that have been irradiated.
⚪️Milky quartz contains small inclusions of liquid and gas, trapped during formation.
👻Rock crystal is clear quartz without inclusions or trace element composition.

These are just some of the many varieties of quartz that can be found all around the world. They are all the same mineral, but with small differences and their own properties!

📷 Amethyst geode, Brazil.
📷 Rose quartz, Brazil.
📷 Prasiolite, locality unknown.
📷 "Herkimer Diamond" Rock crystal, New York.

Welcome to World Cup Wednesday! With the World Cup kicking off tomorrow, we will be highlighting some of our favorite sp...
06/10/2026

Welcome to World Cup Wednesday! With the World Cup kicking off tomorrow, we will be highlighting some of our favorite specimens from World Cup countries! (Part 1/4)

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🇩🇿 Senarmontite. Constantine, Algeria.
🇦🇷 Rhodochrosite. Argentina.
🇦🇺 Stromatolite. Trendall Locality, Western Australia, Australia.
🇧🇪 Hemimorphite and smithsonite. Moresnet, Liège, Belgium.
🇧🇷 Tourmaline. Brazil.
🇨🇦 Fritzonellus truemani. Burgess Shale, British Columbia, Canada.
🇨🇴 Copal with termite eggs and cellulose. Santander, Colombia.
🇭🇷 Nummulites. Gračišće, Istria, Croatia.
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This Tuesday, we are highlighting Nummulites, a superlative ocean-dwelling fossil. Common in the Paleogene to Neogene ar...
06/09/2026

This Tuesday, we are highlighting Nummulites, a superlative ocean-dwelling fossil. Common in the Paleogene to Neogene around 65 to 5 Mya, and still alive in limited numbers today, Nummulites holds the honor of being the largest single-celled organism to ever live. Though most specimens are less than two inches in diameter, the biggest Nummulites fossils have reached a remarkable six inches! Found mostly in the reach of the former Tethys Ocean, Nummulites fossils are common in the limestone of the Great Pyramids and other Mediterranean landmarks. They can also be found in our museum, so come stop by and check them out!

📷 Nummulites, Tertiary Period. Locality unknown. Label shows an alternate name for the genus.

In celebration of World Environment Day, we are highlighting our very own miniature ecosystem! Nestled in the middle of ...
06/05/2026

In celebration of World Environment Day, we are highlighting our very own miniature ecosystem! Nestled in the middle of our museum is a Winogradsky column, a thriving community of bacteria. The only outside ingredient this ecosystem needs to survive is light from the lamp at the top, which powers the photosynthetic cyanobacteria. Below this sits various sulfur producing and consuming bacteria, to some of whom the oxygen is actually toxic! Each layer in the column consumes the products of the other layers, and produces the materials they use for energy.

Come to the museum and check out our own ecosystem in action!

📷 Winogradsky column, full view.
📷 Close-up of top two layers of Winogradsky column.
📷 Close-up of bottom two layers of Winogradsky column.

We love rainbows, and one of our favorites today’s Mineral Monday subject, labradorite! Labradorite is a plagioclase fel...
06/01/2026

We love rainbows, and one of our favorites today’s Mineral Monday subject, labradorite! Labradorite is a plagioclase feldspar that sits towards the Ca-rich end of the spectrum, found in mafic rocks such as gabbro and basalt. It is most famous for labradorescence, its namesake optical effect.

Labradorescence is a rainbow shimmer effect caused by long, thin formations called “exsolution lamellae” in crystals of labradorite and similar feldspars. Because the composition of labradorite is not stable as a solid mineral, it deposits as two separate compositions making up lamellae. When these lamellae are the right width, they interact with light waves to make the rainbow shine the mineral is known and loved for.

Labradorite is one of Earth’s most beautiful rainbows. Look for it next time you see a piece of gabbro!

📷 Labradorite, Labrador, Canada. Donated by Peter Duehr.

We're celebrating wrapping up this season of new beginnings by highlighting a final "Spring Starter"; special specimens ...
05/29/2026

We're celebrating wrapping up this season of new beginnings by highlighting a final "Spring Starter"; special specimens that evoke new beginnings over Earth’s history!

Our last Spring Starter is Captorhinus aguti, an early, hook-nosed tetrapod that roamed the supercontinent Pangea between 300 and 250 million years ago. When Pangea broke up, it took C. aguti fossils with it, everywhere from Texas to China! C. aguti sports many traits seen in modern creatures, such as a quadrupedal gait, scaly skin, and a triangular skull similar to those seen in reptiles. They also had more mammalian traits, such as the foot splay that allow primates to walk upright. The genus Captorhinus might also have been the first to develop caudal autonomy, or the ability to sever an appendage like a tail for defense.

Being such an old and widespread species has led to some debate about the relationships between C. aguti and more modern species. They have been theorized to be primitive reptiles, the ancestors to turtles, or, most recently, as relatives to early amniotes. Many of these new hypotheses have come as new fossils and species are found, revealing more traits in C. aguti that lead scientists to revise old models.

The Permian Period was a time of major changes, from the collapse of the Carboniferous rainforests and the breakup of Pangea to the apocalyptic P-T mass extinction event that ended it. It was always unlikely that this species itself would survive until modern day, but they provide information that help us understand the evolution of species we do have now. Swing by the exhibits and look for this special creature on its perch.

Photo 1📷 - Captorhinus aguti fossil, prepared by Chris Pladziewicz, 1993.

Today we are celebrating tour guide and recent Geological Engineering graduate Mariel! Originally from Menomonee Falls, ...
05/28/2026

Today we are celebrating tour guide and recent Geological Engineering graduate Mariel! Originally from Menomonee Falls, WI, Mariel has spent the last two years giving tours at the Museum, and her favorite part is the enthusiasm that people show when they ask in-depth questions on tour that allow her to dive beneath the surface level – just like her favorite specimen, the Platecarpus! When not giving tours, Mariel likes to take rides on her longboard.

Post-graduation, Mariel is looking for an entry-level engineering position outside the Midwest. One of her goals is to stay connected to earth science in the role she takes. We wish her the best in her future endeavors!

Today we are celebrating tour guide and tour coordinator Anna! Anna is originally from Oregon, WI, and has recently grad...
05/27/2026

Today we are celebrating tour guide and tour coordinator Anna! Anna is originally from Oregon, WI, and has recently graduated with her B.S. in Environmental Science and History. Anna’s favorite specimen in the museum is the Platecarpus, which she attributes to its interesting story. She thinks being a tour guide is a rewarding experience, and she love teaching people and meeting people from all over who want to learn about geology. In that vein, last summer she gave Governor Evers a tour of a bog while she was working at a nature center in northern Wisconsin!

In September, Anna will start her Master’s in Environmental Education at the University of Minnesota Duluth. While there, she will work in developing education programs for the Voyageurs Conservancy. We wish her the best as she continues to inspire young minds!

As we wrap up the spring season, we're celebrating this season of new beginnings, and highlighting some Spring Starters;...
05/22/2026

As we wrap up the spring season, we're celebrating this season of new beginnings, and highlighting some Spring Starters; specimens that evoke new beginnings over Earth’s history.

This Spring Starter is one you might have heard of before. Archaeopteryx originally gained fame when it was found just a few years after Charles Darwin published On the Origin of Species. It is heralded as an example of a transition fossil, exhibiting traits of dinosaurs and birds.

With new technologies for examining fossils, scientists are continuing to learn about these creatures and their place in the evolutionary tree of life. For example, scientists at Chicago’s Field Museum Archaeopteryx have used CT scans and UV light on their Archaeopteryx specimens to reveal soft tissue details, including scales on the bottom of the creature's toes and bumps on the roof of its mouth. Their research into the fossil’s feathers leads them to claim that Archaeopteryx could indeed fly, but likely in short bursts, similar to a chicken.

Despite being known for over 160 years, new techniques keep shedding new light on old fossils. Swing by the museum and take a peek at this flying pioneer!

Photo 📷 - Archaeopteryx fossil cast, on display at the Museum.

The Geology Museum will be closed on Monday, May 25, in observance of Memorial Day. Regular hours will return for the re...
05/22/2026

The Geology Museum will be closed on Monday, May 25, in observance of Memorial Day. Regular hours will return for the rest of the week.

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