On a trip with so many highlights, it’s hard to pick only a few. But if pressured, I would give first prize to the A.E. Seaman Mineral Museum, which is part of Michigan Tech. I literally had to pry my feet from the floor and force myself to move on to the next exhibit. After three hours, I had only seen half of the items. We went back on the same $8 ticket the next day it was open. My colleague was very patient and enjoyed the benches, while I barely noticed my aching feet.

Figure 2 shows a bismuth crystal, which I bought in the gift shop. I had one some years back, but maybe one of my students took it home. A professor in Germany grows these in a lab. I had imagined that there is some type of chemical treatment to get the rainbow of colors while maintaining the very shiny appearance. However, multiple sources indicate that the hues result from varying thickness of the naturally forming oxide layer on the surface.

It always amazes me to be able to see evidence of the crystal structure of a material in the form of regular crystals. The angles between the crystal facets look pretty square to me, but multiple references indicate that bismuth has a rhombohedral structure. It’s similar to a cubic shape but slightly distorted. (One diagonal of the cube is elongated, others shortened.) The two images in Figure 2 are of the same crystal, although it is hard to mentally rotate them to predict one view from the other.

The curators at the Seaman Museum did a really wonderful job of displaying the artifacts for both aesthetic appeal and educational purposes. Figure 3 shows a little gizmo used to measure the angles between the facets of crystals. The gizmo was in the first section to welcome visitors, which was aptly titled “The Beauty of Minerals."

I was really surprised to find a pyrite (iron sulfide, FeS) crystal in the shape of a disk (Fig. 4). The radiant appearance of the graphite nodule is visible in cross section, while these “pyrite suns” apparently grow in this flat configuration. The larger-appearing sun now resides with me after I spent more money at the museum gift shop. I don’t recall seeing an explanation for why these suns grow in a thin disk shape when most pyrite is cubic (or nearly cubic if there are impurities).

Other displays explained that the flat copper deposits in the UP resulted from copper depositing itself in narrow spaces between existing rocks as the temperature, and thus solubility, of the copper-rich water filling the crevices dropped. Maybe something similar is happening here, but the display piece looks more like the pyrite pre-existed the surrounding rock.

Another thing I learned at the museum is that rocks can have other minerals intrude in cracks, and then the original rock can somehow be transformed into something else. Geology is REALLY complicated!

On a trip with so many highlights, it’s hard to pick only a few. But if pressured, I would give first prize to the A.E. Seaman Mineral Museum, which is part of Michigan Tech. I literally had to pry my feet from the floor and force myself to move on to the next exhibit. After three hours, I had only seen half of the items. We went back on the same $8 ticket the next day it was open. My colleague was very patient and enjoyed the benches, while I barely noticed my aching feet.

Figure 2 shows a bismuth crystal, which I bought in the gift shop. I had one some years back, but maybe one of my students took it home. A professor in Germany grows these in a lab. I had imagined that there is some type of chemical treatment to get the rainbow of colors while maintaining the very shiny appearance. However, multiple sources indicate that the hues result from varying thickness of the naturally forming oxide layer on the surface.

It always amazes me to be able to see evidence of the crystal structure of a material in the form of regular crystals. The angles between the crystal facets look pretty square to me, but multiple references indicate that bismuth has a rhombohedral structure. It’s similar to a cubic shape but slightly distorted. (One diagonal of the cube is elongated, others shortened.) The two images in Figure 2 are of the same crystal, although it is hard to mentally rotate them to predict one view from the other.

The curators at the Seaman Museum did a really wonderful job of displaying the artifacts for both aesthetic appeal and educational purposes. Figure 3 shows a little gizmo used to measure the angles between the facets of crystals. The gizmo was in the first section to welcome visitors, which was aptly titled “The Beauty of Minerals."

I was really surprised to find a pyrite (iron sulfide, FeS) crystal in the shape of a disk (Fig. 4). The radiant appearance of the graphite nodule is visible in cross section, while these “pyrite suns” apparently grow in this flat configuration. The larger-appearing sun now resides with me after I spent more money at the museum gift shop. I don’t recall seeing an explanation for why these suns grow in a thin disk shape when most pyrite is cubic (or nearly cubic if there are impurities).

Other displays explained that the flat copper deposits in the UP resulted from copper depositing itself in narrow spaces between existing rocks as the temperature, and thus solubility, of the copper-rich water filling the crevices dropped. Maybe something similar is happening here, but the display piece looks more like the pyrite pre-existed the surrounding rock.

Another thing I learned at the museum is that rocks can have other minerals intrude in cracks, and then the original rock can somehow be transformed into something else. Geology is REALLY complicated!