UNIVERSITY PARK, Pa. — Peter Heaney, professor emeritus of geosciences, retired on June 30 after a 27-year career at Penn State. During his career, he inspired many students in the geosciences and other majors through his teaching and research. For this, he has won many accolades, including the Atherton Award for Excellence in Teaching in 2023.
His impact on students through his dedication to teaching inspired Mara Grigore, who took his "Geoscience 201: Earth Materials" class this past spring semester, to interview him about his career. Grigore is a rising senior and Schreyer Scholar majoring in Earth science and policy, with minors in geographical informational systems, environmental engineering and political science.
“Dr. Heaney is the best professor I have ever had the privilege of taking a class from,” Grigore said. “He truly has the magic touch when it comes to teaching and engaging with students. Going into his class as an earth science and policy major, I was not very excited to take a class solely about rocks. But I have never been so humbled in my life. Each lecture was as if Dr. Heaney was crafting a story — engaging, captivating and relevant to today’s physical environment. Dr. Heaney made a class about rocks fascinating. It was an absolute pleasure to take his class.”
Grigore said that since Heaney was retiring from Penn State this summer, she wanted to interview him to learn more about his career.
“As he is retiring from Penn State, I wanted to share my incredible experience of being his student by interviewing him,” Grigore said.
Grigore also collected quotes from other students who took the "Geoscience 201" class and from Heaney's colleagues:
- "Dr. Heaney was one of the most knowledgeable and passionate professors I have had at Penn State. He truly cared about both the course material and the students, which could be seen in his lectures and field trips." — Marsella Degnan, undergraduate student
- “Dr. Heaney was the most passionate and kind professor I've ever had. He truly cared about his students, and his class made me extremely excited to enter the field of geosciences.” — Ty Wholf, undergraduate student
- “Dr. Heaney is easily my favorite professor. You can clearly tell that mineralogy is his passion, and it presents itself in his teachings. I'm not a geoscience major. His class was never something I really expected to take, but despite that, I felt as if I have learned far more in his class than any of my other classes. Dr. Heaney had a special talent when it came to keeping people engaged and teaching his students in the best way possible. I think he is what other professors should strive to be, and I am sad I won't be able to experience a class like this again.” — Alec Sikora, undergraduate student
- “Peter represents the model scientist to me; someone who is driven by genuine curiosity and a passion for teaching others what he has learned. It’s always a joy to hear about what he’s been working on and thinking about.” — Christopher Gorski, professor of environmental engineering
- “Dr. Heaney is one of the first professors I ever served as a teaching assistant for, and it was amazing working for someone who cares so much for his students. He is the kind of professor that reminds you why you want to teach to begin with.” — Denali Kincaid, doctoral student in geosciences
- “Throughout his career, Peter has been a thoughtful and caring educator, an engaged and accomplished scientist, and a dedicated and insightful member of our community. We will miss his valued contributions to all we do.” — Charles Ammon, professor of geosciences
- “Peter is the best of colleagues, in my opinion: He is easy to talk to, he is considerate of others and their opinions, he is not afraid to speak his own mind (but does so thoughtfully and with due consideration for others), and he supports the geosciences community at Penn State. … who else bakes brownies, cakes and cookies with his own hands to feed the audience at a Geochemistry Forum talk on a Friday afternoon? Peter loves teaching, and is dedicated not only to the craft of doing so, but also to the students. He is one of those people who truly care. From a research perspective, Peter is focused on gaining a deep and clear understanding of complex and sometimes convoluted processes and questions. He doesn’t shirk from a challenge. I cannot say enough about Peter, and my enjoyment of the interactions that I have had with him over the past approximately 20 years.” — Mathew Fantle, professor of geosciences
Grigore’s interview with Heaney is shared in the following Q&A.
Q: Why should people care about rocks?
Heaney: Every rock contains a chapter of Earth’s history. Rocks are formed by Earth processes; thus, they record some information about the ancient Earth. Rocks are the evidence that we use to reconstruct this 4.5 billion-year tapestry of Earth’s existence. Geologists have developed ingenious ways to pull little threads of that tapestry out of the rock to interpret the history of the Earth.
Q: To whom would you recommend a career in geosciences?
Anybody who is fascinated by the history and the future of the Earth. We care about Earth's history because it will tell us about Earth's future.
We live in a new geologic age where everything is being influenced by humans. In the year 1800, no one would have believed that we could alter the climate or change the pH of the oceans due to the emissions from burning so many fossil fuels, but we are now seeing the impacts of human activities.
To understand how the Earth may be changing in response to what people are doing, we need to look to the past. It's not the first time that an organism has utterly transformed the Earth. When photosynthesis first appeared 3.5 billion years ago, it took a billion years for the atmosphere and ocean to reflect the presence of oxygen. But between 2.6 and 2.2 billion years ago, the Earth's atmosphere was oxygenated — a major transformation that likely killed off a lot of organisms that could not tolerate oxygen in the atmosphere.
The Earth has been through these major transformations before, but we really need to look into Earth’s history to understand that it is possible for us to radically transform the Earth in a way that is going to be detrimental for humans.
Secondly, I’d recommend geosciences to someone who is curious about natural processes, a person who just wants to know for the sake of knowledge. For instance, someone might wonder why goethite, which is the mineral that makes up rust, can sometimes exhibit absolutely gorgeous rainbow colors.
Q: Could you sum up your specialization in environmental mineralogy and crystal structure analysis?
Heaney: I always like to joke that my research extends from gems to mud. I offered an honors course on the science of gemstones when I came to Penn State in 1998. It was the first honors course that the Schreyer Honors College offered in the College of Earth and Mineral Sciences. I designed this course for English majors who were not really comfortable with math and science. I wanted to demonstrate that gemstones could be a vehicle for learning. The students could learn some high-level material sciences, physics and optics, just so long as we were relating the material back to gemstones.
The other side of my research has been in environmental mineralogy, which analyzes the role that minerals and soils play in cleaning our environment. For example, there's a class of minerals that I've been studying called manganese oxides, which are found at levels of less than 1% of most soils. Despite their low concentrations, manganese oxides mediate complex oxidation and reduction processes. Take for example, chromium; when in the trivalent state it is benign, but some manganese oxides can transform it into hexavalent chromium, which can be cancerous. So, they can transform some elements from being safe to being dangerous for humans. On the flip side, manganese oxides are beneficial as they sequester nasty elements within their crystal structures.
Much of my research focuses on interactions between soil minerals and groundwater. I use time-resolved X-ray diffraction to observe these processes in real time at the atomic scale. This involves flowing a fluid with dissolved ions like chromium through mineral powders in a glass capillary, then passing X-rays through it to track structural changes — such as when radioactive cesium is absorbed. Since this requires high-intensity X-rays, I conduct the work at the Argonne National Laboratory near Chicago.
Q: Can we assume this is a great solution because manganese oxides are natural elements good for use in environmental remediation?
Heaney: Yes, a good example of this is in eastern Washington, where a World War II-era lab produced plutonium. After the war, radioactive waste, including cesium-137, was stored in concrete tanks near the Columbia River. These tanks have begun to crack, allowing radioactive fluids to seep through the soil toward the river. Beneath them lies the Richland Formation, abundant in manganese oxides, which may help trap cesium-137 and prevent its spread.
Q: What one research finding in your career is most important to you personally?
Heaney: The research that I'm most proud of is where I try to explain how chalcedony, a type of quartz, forms. It’s not one of my most heavily cited papers but it is my favorite. Let me explain why.
When I got to college, I started out on a pre-med track. By the end of my sophomore year, it was really clear that I was not meant to be a medical doctor. I took a summer course at SUNY New Paltz in archaeology where we were excavating a rock shelter full of projectile points made from fine-grained material called chert or flint. Back at Harvard University during my junior year, I took my first mineralogy class and fell in love with it. That led me to graduate school at Johns Hopkins University, where I conducted research on distinguishing cherts with a transmission electron microscope — challenging work, since cherts are nanocrystalline and randomly oriented. During this, my adviser suggested looking at agates and I noticed something that jumped out at me. It was this abrupt transition from one layer to the next.
I was looking at chalcedony in agate — a variety of the silica mineral quartz that has parallel banding. I questioned what caused the alternating bands of microcrystalline chalcedony and coarse grains of quartz. I was drawn to that question because geology often shows these toggle-switch behaviors instead of a more subtle transition from one mineral variety to the next. As a fifth-year graduate student, I built a model to explain all the oddities that chalcedony exhibits. It turns out, depending on how silica tetrahedra link up, you get either left- or right-handed quartz — which ultimately explains that toggling we see in nature.
I think this was my favorite research finding partly because it was my first idea without my adviser’s involvement. It also hasn't been proven wrong yet.