Missing Minerals

3/1/13

Today, I started my internship by cleaning out the barite capsule we had put in the furnace last week. The barite looked a little dark like one of our previous galena experiments, which worries Daniele about contaminants possibly interfering with the experiment. I have found the perfect balance between shattering the capsule all over the lab and not cracking the glass, and I was actually quite proud of my experienced tap that quickly halved the capsule. I recycled the sulfur-34, removing it from the sides of the capsule with ethanol, but the barite crystal was giving me a little trouble as it was trapped within the sulfur. I filled up a beaker with ethanol and then placed the barite in the ultrasonic. Here are some pictures from last week that Heather and I took of the barite.

 As you can see, it is a clear crystal, so we placed the crystals on some purple post-it notes so that they would show up more clearly under the light microscope. After putting the barite in the ultrasonic, Daniele, Heather and I headed down the hall to work on some more simulations. We worked on data from two different sphalerite minerals and I practiced learning which data to manipulate in order to match the simulation's graph with our data. For example, if the peak on our simulation's graph for the sulfur-34 was higher than that of our data, I would change the ratio of sulfur-32 and sulfur-34 in the simulation, making the sulfur-34 lower so that peak would be lower. With this data manipulation, practice makes perfect as I began to figure out how thick to make a layer of sulfur in order for the simulation graph to line up and how to slowly decrease the sulfur-34 levels. The sulfur-34 should decrease throughout the sphalerite as you get to deeper and deeper layers because the sulfur will have a harder time penetrating. That information must be reflected in the simulation where the graphs must line up and have the sulfur-34 values decrease over time until only the sulfur found within the sphalerite sulfide is present. After working on graph manipulations, we headed back to the lab to look at our barite crystal. We decided to give it a few more minutes in the ultrasonic and begin working on another barite capsule. After filling a glass tube with a sealed end with a carefully selected barite mineral with a polished surface and some sulfur-34, I hooked up the tube to the vacuum to be evacuated. While I was doing this, Heather checked on the barite crystal and took it out of the ultrasonic. Sadly, when Heather was removing the barite from the ultrasonic and trying to transfer it to the light microscope, our sample went shooting out of the tweezers and somewhere into the vicinity. The fact that the crystal was clear made our quest all the more difficult as we began searching the lab floor on our hands and knees searching for our missing experiment. Though I tried to linger as long as possible, I had to leave for my shuttle back to Emma, but hopefully Daniele and Heather were able to relocate the missing crystal. If not, we'll have a new barite capsule to put in the furnace next week and hopefully some more work with simulations. I will also have to work on making a few more glass tubes with sealed ends for our capsules next week since our supplies are running low.