Crystal Creations

3/15/13

When I walked into the lab today, Daniele was having a discussion with Dr. Watson, so I decided to go out into the hall and take a closer look at the displays and some of the posters. One display showed a multitude of rocks that could be found around New York State. I spent a while looking at the slate (which I have often seen while hiking or in my grandma's backyard) and took a little pride in being able to recognize a few (by which I mean a very few) number of the rocks on display. Right before Daniele was done with her conversation, Heather walked in and we began to clean out the barite crystal that we had put in the furnace last week. This crystal was not enclosed by the sulfur because the capsule had cooled while resting on its side, causing the sulfur to dry along the sides of the capsule rather than encasing the crystal. After easily removing the crystal, we spent the rest of our time in the lab making two new capsules, one containing barite and the other celestite. We started with the barite crystal. I hunted through our drawer in the lab, eventually finding the barite crystals we had polished a few weeks ago. I quickly made the capsule with my ever increasing Bunsen burner abilities. Finding a celestite crystal to do an experiment on was a little more tricky. As I explained last week, the celestite crystals are very prism-like and have lots of small flat surfaces. That makes it difficult to find one large flat surface that would be sufficient for an experiment.

After finally finding a crystal, Daniele showed me a huge block of synthetic quartz. I have to admit I have a soft spot for shiny things and the quartz had me enraptured. It was a huge block about the length of my hand and almost perfectly clear. It looked a lot like glass except it's density was different along with the texture. Daniele then showed me more crystals that the lab had bought and collected over the years, including bright green yag.

Our crystal was not cut like this one above, but it gives you an idea of what yag looked like when previously I didn't even know yag was a word.
She also showed me some beautiful crystals each about the size of my thumb that had cost a whopping $1500. I was blown away that the crystals that were being experimented on in the lab could cost so much. Daniele then talked about how many crystals could be grown using a seed, which would then be built upon layer by layer until the crystal had formed. We then had to quickly wrap up our conversation on crystals because I only had 10 minutes to evacuate and seal my celestite crystal. After sealing the capsule with an expert's touch, I carried my two capsules to the furnace. There we put both capsules on one thermocouple so we could run the experiment simultaneously and only use one furnace. We ran the experiment at 500 degrees Celsius, and hopefully we won't have any complications. I hope to have some new date to look at when I return to the lab with our growing data on our sulfate crystals.

Stealing Sulfates

3/08/13

Heather emailed right before I left for my internship saying that she would be late coming in today, so I braved the snowy weather to start my day cleaning a capsule with Daniele. We went into the furnace room where we removed the capsule with barite in it that we had made last time before taking it to the lab to recycle the sulfur-34 and remove the crystal. While there, Daniele told me that Heather had been able to find the barite crystal that had gone flying out of the tweezers last week. This is great, because now with two barite crystals, Daniele can start to make a profile on this sulfate that she has never experimented with before in order to figure out a basic idea of how sulfur diffuses through barite. The crystal didn't give us too much trouble when removing it from the capsule though it did have to go in the ultrasonic a few times, but we quickly had the  crystal extracted in no time. At this point Heather had showed up, and we decided to hunt down a few more sulfates to experiment on. After hunting down several different keys, we opened the display case outside the lab and sneakily chiseled away at some of the minerals. Dr. Bruce Watson had given Daniele two containers of barite, so we now had quite the collection of sulfates.

The picture on the left is all of our sulfates with the two barite minerals on top and our thieved  minerals below. The minerals we chipped away at are gypsum and celestite. Celestite in the picture on the right is on the left and was in small crystals forming a large mineral. Celestite is a strontium sulfate. The gypsum is the rightmost container and is a calcium sulfate that also contains water. The crystal we took those small chips from was huge and had to weight about 40 pounds. It was a very soft mineral so it was pretty easy to chip off a few flaky pieces and head back to the lab. Daniele decided for us to use one of the barite crystals Dr. Watson had give us, and after looking at a nice crystal with a flat surface under the microscope we saw the crystals were very good quality with hardly any inclusions. We were running out of tube to form capsules with, so with a diamond cutter that looked a lot like a pen except with a small diamond for the tip, I cut a few tubes and sealed the bottoms with the Bunsen burner to create one half of the capsule. After placing these tube in the drying oven to remove any moisture within the tube, I placed my barite crystal and sulfur-34 within the tube. I used the vacuum to evacuate the capsule, I quickly sealed it off and had a ready-to-go capsule. It was then time for me to run so before the capsule had even cooled, I had to run out the lab in order to make it to the shuttle on time. Daniele is going to get some more data from the crystals on Monday when she uses the ion beam and hopefully I'll be able to look at some of this data next week. I'm also looking forward to doing some more experiments with different sulfates.

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.