Finally, I have a scientific paper published! I am an official author, first author at that! Two years of my life in a 22 page paper on sphene. I do love sphene.
Do you see that little guy? The brown one edging in on some quarts? That's a sphene. They all look like that. Usually they are more orange in color, I think the picture changed the color a little. The big white one is quarts, the big one off to the left is sanidine, and all the black is volcanic glass. This picture is of a microscope slide made from one of my rocks. HRL 21 I bet.
For this picture I crushed up some pumice in a tube with a baseball bat. Then I sorted out the sphene from the glass using water and density differences. Then using a pin taped to a pencil, face grease, and a microscope I picked out individual sphene grains from the "sand" I had made. It was then mounted on a slide by the lovely Danny Flanny at the SHRIMP (Super High Resolution Ion Micro Probe) or a microscope the size of a room. This image was back-scatter imagery. It's been a while, but I think that means they sent something at the grain and what bounced back was recorded as this image. Anyways, each circle is a spot I took a measurement from with the SHRIMP and the numbers are the estimated temperature of the magma (lava) when that part of the sphene grew/formed. I could, but I won't, show you a chart I made with all the temperatures comparing the outside of the grain to the inside, as well as the dark spots to the light spots.
Finally, this last picture is AWESOME! I call it Skeleton Sphene because it looks like bones on the outside of it. That's why I took this picture, because it looked cool. I showed Calvin and it turns out it's actually cool because the sphene on the edges is dissolving and turning into illminite, the bones. That shows that something interesting was happening in the magma at the time of cooling.