Carnegie Museum of Natural History

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Thanksgiving and Nutritional Mineralogy

by Travis Olds

We each have plenty to be thankful and hopeful for this year, but did you know that our traditional American Thanksgiving feast “with all the fixings,” would not be possible without minerals or the people who mine, process, and manufacture the mineral-related materials found in our kitchens?

Kaolinite
Kaolinite. Photo Credit: Debra Wilson

You should thank miners, in part, for the kaolinite clay used to make the fine porcelain china or ceramic plates at your dinner table. When kaolinite is fired in the factory, it partially melts, and crystals of an aluminum-silicate mineral called mullite that hold the ceramic together and give it high heat resistance form on cooling. Also, whether you eat and serve food with silver, steel, or aluminum utensils, extensive work and energy were needed to extract and refine the silver, iron, or aluminum metal necessary for their creation. Silver ore, for example, usually contains many other elements, including lead, zinc, copper, and gold, which can require lengthy chemical or electrochemical processes to separate.

silver on copper
Silver on copper. Photo credit: Debra Wilson

There might also be some unwanted mineral interactions occurring at the dinner table. If your gluttonous Uncle Ned consumes too much salt (sodium) with his gravy and potatoes (high in oxalate) this year, his body may begin to form kidney stones; which are biologically formed minerals made up of crystals of the phosphate mineral struvite and the calcium oxalate mineral whewellite. These biominerals, which can form when your bladder isn’t fully emptied after a sodium or oxalate-rich meal, can be extremely painful, so be sure to drink plenty of water with your meal. Large crystals take time to grow and drinking more water can reduce the concentration of sodium and oxalate in your body, slowing growth of the kidney stones.

Turkey meat, the mainstay of many Thanksgiving meals, also depends heavily on minerals. Did you know that turkeys actually need to swallow small rocks and pebbles, which are made of minerals, in order to digest their food? “Gastroliths,” or stomach stones, are used by other species of birds, reptiles, amphibians, worms, whales, and even some fish to crush their food and provide more nutrients! Fortunately, we humans have a variety of enzymes and strong stomach acids to break down nutrients in the food we eat.

A surprising amount of nutritional science is applied to raising turkeys; their diet is closely monitored and controlled for proper protein and “mineral” content so that they grow large. You have likely heard the term “mineral” applied to many of our dietary items as well, from mineral water, to a variety of products being fortified with vitamins and minerals, or even the advice that it’s important to maintain a healthy balance of minerals in your diet. The term is somewhat misleading because “minerals” in this sense typically refers to individual atomic elements such as potassium or iron, or to other compounds containing these elements, rather than actual minerals in the strict sense. To a mineralogist like me, minerals are naturally occurring crystalline solids made from a specific combination of elements.

hematite
Hematite. Photo credit: Debra Wilson

Most often, the elements essential for our diet have been pre-digested, extracted or processed by another plant or animal, or have been chemically separated from a mineral source that makes it easier for our bodies to absorb. For example, most rice and cereal in the U.S. is fortified with B-vitamins and iron with a coating of finely ground nutrient powder. While the source of iron used in the fortifying powder varies, it all originates with the iron-oxide minerals hematite and goethite. Plants, bacteria, or stomach acids break down these minerals into iron cations that are easier for our body to process.

Thanksgiving vegetable dishes deserve special attention because plants can be the best sources for certain nutrients. In many cases, fruits and veggies grown on the farm also need help with their diet. Feldspar minerals present in soil hold on strongly to certain elements like K, more commonly known as potassium, making it hard for plants to extract this element. Farmers address this problem by using fertilizers like manure, containing predigested and readily absorbed phosphorous, nitrogen, and potassium, to produce a bountiful harvest

This year, please extend a bit of thankfulness to minerals, but mostly give thanks and recognition to the people that work hard to make your Thanksgiving possible; be it a miner, factory worker, your grocer, butcher, farmer, doctor, or all those working behind the scenes and on the front lines that keep us happy, healthy, and well fed.

Travis Olds is Assistant Curator of Minerals at Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences working at the museum.

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Carnegie Museum of Natural History Blog Citation Information

Blog author: Olds, Travis
Publication date: November 9, 2020

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Meet our two new curators!

Dr. Travis Olds

photo of new curator of minerals Travis Olds

Hello! My name is Travis Olds. I’m Assistant Curator of Minerals in the Section of Minerals and Earth Sciences at Carnegie Museum of Natural History. I’m from the Upper Peninsula of Michigan, the northern part of the state that is sometimes confused as being a part of Canada, but also considered by many as one of the most beautiful places on Earth. People born in the U.P., as we call it, are known colloquially as “Yoopers,” and like Canadians we are some of the kindest people you will meet. Many Yoopers have an accent that is best described as a mix between Canadian and Minnesotan; we tend to elongate and over-emphasize vowels in spoken words, with favorites being “ya, eh, you betcha, and don’tchya know.” Our favorite dish is the pasty (“pastee”), a baked meat and vegetable-filled pastry that was introduced early in our state’s history by Cornish miners who traveled to the area to make a living and share their knowledge of mining techniques developed overseas.

Hundreds of mines have operated in the U.P. over the last ~200 years, yielding billions of tons of iron and manganese used for the steel produced here in Pittsburgh, and millions of tons of copper used across the world for plumbing, electrical lines, and electronics. Although many mines in the U.P. have long been abandoned, a few iron and copper mines are still in operation today. For several generations my family has made a living working in the mines, including my father and uncle, who were large influencers to my interest in minerals.

As I started collecting and learning more about minerals I became fascinated by radioactive minerals, the ones containing uranium and thorium. Uranium minerals come in many beautiful shapes and colors. They sometimes fluoresce neon green and yellow colors under UV light, and emit invisible high-energy particles during their decay. Although we owe our basic understanding of X-rays and many modern medical technologies and treatments to early studies of radioactive minerals, uranium remains one of the most controversial elements on the periodic table. It has been used to create exceptionally valuable technology but has also created unimaginable evil and pain. In the future, I believe nuclear power will likely become one of the dominant methods for producing “base-load” power to replace the antiquated and highly pollutive coal and natural-gas burning energy plants. I study the atomic arrangement and properties of uranium minerals because they are good analogs for advancing several aspects of nuclear power generation, from mining to processing and storage of used fuel and waste. My mineral collecting trips have taken me to unique places underground in Colorado, Utah, and the Czech Republic, and thanks to the group of friends and researchers that I work with, I have been lucky to find and describe 20 new minerals. At the museum, I research minerals to improve technology and better understand how humans are changing the minerals found on the Earth’s surface.

Photos of our new minerals can be found on my Mindat.org page.

Dr. Carla Rosenfeld

photo of new curator of earth sciences Carla Rosenfeld

Hello! I’m Carla Rosenfeld, the new Assistant Curator of Earth Sciences in the Section of Minerals and Earth Sciences at Carnegie Museum of Natural History. I received my Ph.D. in Soil Science and Biogeochemistry from Penn State and a B.S in Chemistry from McGill University. Following my Ph.D., I worked as a postdoctoral fellow at the Smithsonian National Museum of Natural History and University of Minnesota. After several years away, I am so excited to be returning to Pennsylvania to continue my research!

As a researcher, I am an interdisciplinary environmental biogeochemist. I use tools from mineralogy, geochemistry, and microbiology to study how pollutants and nutrients behave in the environment. I am fascinated by how biology, geology, and chemistry interact – for example when plant roots scavenge nutrients from soils by dissolving minerals, or when organisms form biominerals (think teeth, shells, and corals). Understanding how living and non-living things interact in different environments helps us to understand and predict how nature will respond to changing climate and other human impacts. Because I’m interested in how microbes make and alter minerals in soils, I’ve visited all sorts of places to collect soils, plants, water, and microbes (mostly bacteria and fungi). I’ve been down to the bottom of the deepest and oldest underground iron mine in Minnesota (Sudan Mine, ~ 1 mile below the ground surface!), to hot springs and the world’s only captive geyser in Idaho, and, right here in Southwest PA, to acid mine drainage remediation systems! Outside of science, I love to spend time outdoors biking (I even biked across the US from CT to CA one summer), mushroom hunting (my favorite mushrooms to find are golden chanterelles, Cantharellus cibarius or Cantharellus lateritius), and generally spending time outdoors. I also love to bake (including science cakes!), and I’ve kept a spreadsheet detailing everything I’ve baked for the last 5 years!

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The Mineralogy of Ice Cream

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The Mineralogy of Ice Cream

by Travis Olds

Have you ever made ice cream at home?

You may have noticed that homemade ice cream has a different texture than what you buy at the grocery store or get at an ice cream shop. Homemade ice cream can taste “grainy” with a coarse texture, unlike the creamy Ben and Jerry’s from the store. This is because ice crystals in homemade ice cream are usually much larger than the ice cream made by professionals.

close up of ice crystals
“Ice Crystals”by glenngurley is licensed under CC BY-NC-SA 2.0

This is where mineralogy comes in. In nature, large mineral crystals take time to grow, sometimes growing for up to 100,000 years or more! The same is true for ice and snow, which happen to be minerals too. The shape and size of snow crystals that fall from the sky are controlled intricately by the outside air temperature, relative humidity, and time. Snowflakes are usually largest when they spend a long time in the air and at temperatures a bit below the freezing point, near 15 °F. At colder temperatures, the crystals grow quickly and are smaller. Fortunately, we won’t be seeing snow for a while, however, summer can bring even larger balls of ice from the sky! During thunderstorms, hail stones can grow VERY large (up to 15 cm or nearly 6 inches in diameter), sometimes spending up to 30 minutes swirling around updrafts in the icy and rainy conditions within storm clouds.

two-inch piece of hail next to ruler in the grass

To make a smooth and creamy ice cream, companies like Ben and Jerry’s use freezers cooled to very cold temperatures, -40 °F, that quickly freezes the cream thereby producing tiny ice crystals. Ice cream prepared at home is made with a salty mixture of ice and water that can reach nearly -5 °F, but at this temperature the ice crystals grow more slowly and larger. When the crystal size reaches about 50 micrometers, roughly the width of a human hair, your mouth senses the coarse texture.

Three steps you can take to make creamier ice cream at home:

1.     Use a higher fat content by adding more cream. More fat will “spread” out water molecules in the cream, creating more nucleation sites, or growth places, for ice and smaller crystals.

2.     Using crushed ice, instead of ice cubes, will bring the ice/salt mixture to a lower temperature. Also, pre-chilling the cream and sugar before placing it in the salt bath will help speed up freezing, producing smaller crystals.

3.     Use “dry ice,” or frozen carbon dioxide, available at many grocery stores, for even lower temperatures and faster crystallization. But be careful, dry ice should only be used with proper gloves and under adult supervision.

Travis Olds is Assistant Curator of Minerals at Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences working at the museum.

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Thanksgiving and Nutritional Mineralogy

Carnegie Museum of Natural History Blog Citation Information

Blog author: Olds, Travis
Publication date: June 16, 2020

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What Do Minerals and Drinking Water Have to Do With Each Other?

In the same way scientists discover new plant or animal species, new minerals are usually found by exploring new places with hard work and determination, but also sometimes by pure chance and luck. In fact, you do not need to be a scientist to make exciting discoveries. You do need, however, to follow the basic steps of the scientific method when doing any research: (1) first ask a question you are interested in; (2) research that question; (3) develop a hypothesis; (4) test it; (5) analyze the data your tests generate; (6) draw conclusions; (7) and communicate the results.

When describing a new mineral, mineralogists like me gather a slew of analytical data about the atomic arrangement, chemical makeup, and optical and physical properties to completely characterize the mineral. The data we gather is recorded and accessible, so that when others find similar crystals the analytical data for those specimens can be compared. Allowing your findings to be further tested and improved, or even shown to be wrong, forms the foundation of all fields of science and medicine.

tiny hydroxylpyromorphite crystals
A microscope image of tiny transparent crystals of hydroxylpyromorphite from the Copps mine, Marenisco, Gogebic County, Michigan. Field of view is 0.45 mm. 

I recently gathered analytical data for the new mineral hydroxylpyromorphite, a mineral with a mouthful for a name, but one that is extremely important to removing toxic lead from drinking water. Hydroxylpyromorphite is a lead phosphate mineral, and part of a larger group of minerals with related crystal structures (the arrangements of atoms) called the apatite group. Our bones and teeth are made of apatite, calcium phosphate, and the natural processes that move this critical building block throughout our bodies are disrupted when exposed to lead, potentially causing brain damage and other diseases. Lead is especially dangerous to children, and to prevent lead poisoning, water treatment plants often add phosphate to the water supply. Under the right conditions, phosphate grabs strongly onto lead atoms, forming hydroxylpyromorphite and removing it from the water. Until our description, the crystal structure of this mineral was unknown. Now that we understand the crystal structure, the information can be used by others to develop better techniques or processes that reduce lead in drinking water.

Travis Olds is Assistant Curator of Minerals at Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences working at the museum.

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Fungi make minerals and clean polluted water along the way!

Fungi are all around in the environment. For example, the mold that invades wet basements, the mushrooms that we cook with, and the yeast that people use to make bread, wine, and beer are all members of the fungal kingdom. Fungi are also essential parts of natural ecosystems, breaking down complex carbon compounds like dead leaves or bark and returning nutrients to the soil. In addition to all this, many fungi are also extremely tolerant of polluted environments and can transform pollutants from highly toxic dissolved forms to less or non-toxic solid forms.

photo of biominerals being formed by fungus
Biominerals being formed in a flask by fungus, Paraconiothyrium sporulosum (pink color is Se(0) biominerals and brown color is Mn oxides).

Between 2016 and 2018, as a postdoctoral fellow at the University of Minnesota, I led a small research team in an investigation of how common soil fungi responded to two environmental pollutants, manganese (Mn) and selenium (Se). Our study, published in the journal Environmental Science & Technology, was entitled, A fungal-mediated cryptic selenium cycle mediated by manganese biominerals. For our study we used two different species of fungi from the lab’s culture collection, a resource that contains microbes isolated from natural and polluted environments all over the US. Both elements investigated are micronutrients and important in small amounts, but can be harmful at high concentrations, such as in coal mine drainage where they are highly abundant.

Two fungal cells surrounded by Mn oxides (thin black rods) and elemental Se (black circle) biominerals imaged using a transmission electron microscope.

We knew that under certain circumstances the fungi make biominerals, a subset of solid minerals formed through biological activity. So, we designed an experiment to track the fate of the pollutants during fungal growth. What we observed was that the fungi did, in fact, turn dissolved forms of our targeted elements into solid biominerals. Using a variety of geochemical techniques including a high-powered electron microscope, we identified manganese oxide and elemental selenium biominerals formed side-by-side, indicating that they can coexist in natural environments. The Mn oxides also seemed to recycle some of the Se back to dissolved forms, which is exciting because this transformation indicates there is a cryptic, or ‘hidden’ part of the natural Se cycle that was previously unknown. We are now working on follow-up engineering experiments using these same fungi to see if they can effectively remediate different types of contaminated wastewaters. We’re hopeful that these fungi can offer low-cost, low-input alternative remediation solutions for a wide variety of environmental clean-up applications. In the meantime, we’re also studying other biominerals that our fungi make and collecting new biomineral-forming fungi.

Carla Rosenfeld is the new Assistant Curator of Earth Sciences at Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

Article citation:

Rosenfeld, C.E, Sabuda, M.C., Hinkle, M.A.G., James, B.R., Santelli, C.M. A fungal mediated cryptic selenium cycle linked with manganese biominerals. Environmental Science and Technology 54(6): 3570-3580 doi:10.1021/acs.est.9b06022

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A Rare New Species for Natural History: Earth System Scientists

Part of Anthropocene science is earth system science, the study of anthropogenic change of whole earth systems–the water systems, geological systems, ecosystems, and atmosphere–and their feedbacks with each other and human society. Historically earth system scientists have been a rare species at natural history museums, because they do not collect organismal specimens or valuable rocks. Instead they collect samples of air, water, microorganisms, and soil. But CMNH recognizes these scientists are key to understanding the Anthropocene and translating it to the public.

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Two earth scientists have recently joined CMNH. Dr. Carla Rosenfeld will be the museum’s first curator of Earth Sciences. Rosenfeld’s work focuses on the microbial ecology of earth systems: how they naturally mediate the vast majority of water and soil chemistry and can be used to remediate pollution. For example, she is testing the potential for fungi to remove toxins from acid mine drainage. 

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Dr. Bonnie McGill is a science communication fellow with the Climate and Rural Systems Project (CRSP) in the Anthropocene Science Section. With CRSP she is working with rural communities to explore local climate change impacts, identify the social and ecological systems involved, and design community-level actions. Much of her previous work was in the Midwest studying how soil and water conservation in corn and soybean production impacted greenhouse gas emissions and nitrate pollution of rivers.

Bonnie McGill is a Science Communication Fellow at the Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences working at the museum.