At last we have gotten to the zircon! This last step requires mad-scientist lab gear and some heavy liquids. They’re called heavy liquids because they are relatively dense- and this is what we are using for the final type of separation to get to the teeny tiny zircon. Zircon is a dense mineral (about 4.6 g/cm3) and will sink to the bottom of the slightly less dense heavy liquid, methylene iodine (3.3 g/cm3), while the majority of the other grains will float. (For reference, water has a density of 1 g/cm3).
Did I mention that methylene iodine (MEI) is a carcinogen? That’s why I get to wear this lovely getup (see below).
Like I mentioned above, we are trying to get to the zircon by separating the material based on density. For that we use a seperatory funnel in which we mix up some of the grains in the methylene iodine. The dense stuff sinks and the less dense grains float, leaving a nice boundary between the two. The funnel has a stopper that releases the bottom portion of the liquid including the zircon into one funnel. The rest of the liquid and floating material is collected in a different beaker and we have a separated sample!
A peak into the fume hood where this process takes place. The seperatory funnel full of MEI sits suspended above the beaker that will collect the dense zircon. What’s all the newspaper for? There’s zircon drying under there.
Once dried, we pop the funnel paper with the nearly invisible zircon under a microscope to double check that we have enough good zircon grains. And so far all the samples have produced lots of the tiny crystals!
Next time- maybe a look at the zircon under the microscope.