Saturday, March 5, 2016

Monoammonium Phosphate Crystals from a Kit

I've been eyeing crystal growing kits since I was a kid, so I finally ordered myself one. The one I got is the 4M Crystal Growing Experimental Kit which I ordered on Amazon. Monoammonium phosphate is the chemical used, and the kit came with enough supplies to grow 7 different crystals of various sizes. I followed the instructions from the kit, which essentially involved dissolving the monoammonium phosphate in hot water, letting it cool, then adding the seeding mixture on the surface and leaving it undisturbed for several days. I found a candy thermometer, which was super useful for getting the exact temperatures recommended in the instructions for each step.

Day 1: The set up was completed at 2:00pm on 2/15/16. The kit came with three different seeding colors (blue, white, and red). I mixed the colors such that the small containers would have blue, red, white and purple, the medium ones have light blue and pink, and the large one has light purple. After only a couple hours, the light blue crystal were already forming shards which extended about three quarters of the way up the container. The purple and light purple solutions were too dark to see into, even after shining a flashlight into them. Granted, my little flashlight isn't the brightest.

After 12 hours: The light blue and pink crystals were both of significant size already. I could tell that the pink crystal had a different, more rounded shape than the others. The white and blue crystals were both forming tall skinny shards, the tips of which were just barely sticking up past the surface of the solution. I was surprised at how quickly these particular samples grew.

Day 2: The small red sample was forming very small crystals at the bottom of the container. The blue and white crystals had a couple shards each which were forming past the surface of the solution in really interesting shapes. I began to wonder if I should take them out at that point, since I wanted them to still fit in the provided plastic display containers... but these crystals were so thin that I was worried they would break. I decided to wait one more day.

Day 3: I removed the blue and white crystals to keep them from getting too tall to fit in their cases. I also removed the light blue, medium crystal. Although it was growing quite well, it too had the tips of some of its shards sticking out above the surface. Unlike the smaller samples, however, the tips just seemed to get cut off rather than developing interesting formations above the surface. The medium sample was pretty solid, but the smaller samples were super delicate, and I lost a few small shards during handling.

medium light blue crystal
it probably could have grown bigger if it weren't for the container wall

small blue crystal

small white crystal
piece that broke off
separate white crystal formation

After taking pictures and painstakingly putting them back in their cases, tragedy struck. I dropped the small blue crystal, which fell out of its case and shattered into a dozen pieces. Horrified, the first thought passing through my head was, "but I haven't even named it yet..." Odd because I wasn't actually planning on naming them, but Wilson would have been a good choice. That way when I cried out "Nooooo!" I could have also fallen to my knees and yelled, "WILSON!!!" On the plus side, Wilson's demise doubled my collection of monoammonium phosphate seed crystals, which I'm storing in a ziplock bag for future experiments.
this is all that was left of Wilson...

Day 5: I removed the medium sized "pink" crystal. This one actually came out more red than pink and didn't have the layer of clear crystal the way the light blue one did. I'm pretty happy with the formation however. It was even easier to handle than the other medium sized crystal.
medium pink crystal

Day 8: I still couldn't see into the purple solutions, although quite a bit of solution had evaporated off, especially in the large container. I didn't see crystals poking out of the solutions, so I figured they could use more time.
I could just barely see some crystals forming on the bottom of the small red container, and a couple shards were starting to stick out of the solution and hit the walls of the container. There were also tons of crystals forming on the sides of the container, so I decided to take this one out since I didn't want the crystals on the sides to disrupt further formation. In hindsight I probably could have let the main crystal grow a little bigger and then just knocked off any excess crystal formations. There were two slightly smaller crystal formations in the container as well.
small red crystal

Day 12: I removed the small purple crystals. There were four separate pieces in the container, which turned out more of a pinkish color with clear sections.
small "purple" crystal

Day 15: The solution in the large container (which was supposed to be light purple) had more than half evaporated by this point, and there were three or four places where the crystal was starting to poke above the surface. After removing the crystal, I could see that it looks mostly red overall, but in certain lighting one can see a purple color towards the base of the crystal. This is definitely my favourite crystal of the seven.
large "light" purple crystal
bottom of the crystal

Conclusion: Some crystals definitely grew better than others. In most cases, allowing the crystal to grow above the solution seems to result in the exposed surfaces getting "worn away". I suspect this has something to do with the moisture in the air slowly dissolving the crystals, as the kit instructions recommend keeping the crystals in their display cases after they're complete in order to prevent this. The exceptions to this were the white and blue crystals, which developed formations above the surface of the water; since they grew fast and were only left exposed to the air for a day or two, there wasn't any noticeable "erosion".

Mixing colors didn't yield exact results. For example, the "pink" turned out just looking red, the "light blue" looked about the same as the blue, and the purple looked more pink. Nevertheless, mixing colors did result in a little more variety and had some interesting effects (even if they weren't the expected ones).
the seven crystals in their display cases

I kept a zip lock bag of "seed crystals" that I plan to use in future experiments. Now that I've had the kit experience, I may, at some point, purchase monoammonium phosphate directly and do some research on how to grow these types of crystals from scratch.
monoammonium phosphate seed crystals
shard that broke off from the large crystal

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