(no subject)

[wolffyluna]

I still have not entirely got my feet back under me re:geology, but I'm getting steadier. And the challenges I'm facing are becoming a bit less "erk" and more "eeeeeeeee rocks!"

For one of my classes, are large chunk of that class is a project based around analysing rock samples from some mine or other. The different suites/mines were sort of-- auctioned off? Like, the lecturer advertised them one at a time, and it was first in best dressed to get them. And I think all of us felt they got sold a pup, afterwards. For example, mine is a suite that they're doing for the first time this year. Which means it doesn't have any polished sections (basically a chunk of rock set in a epoxy, and polished to a very shiny finish, for microscopy purposes). So I have to make my polished sections. Which isn't difficult but it is time-consuming and fiddly, and it's possible to screw up in a way that mean you have to start over. (It largely involves sanding rocks. By hand. With, like, 8 different grits.)

My suite was a Peruvian skarn with lots of garnet, and some copper and zinc bearing ores. And I could not identify the minerals in at all. I couldn't find the garnet, because most of the rock was garnet and I was looking for individual grains. (In my defense, said garnet was also lime green. Which is a colour garnet can be. But it's still confusing.)

But I've got a better handle on it now, and I am feeling proud of myself for one feat of mineral identifying. In some of the rocks, there were these fine veins of something shiny and pale-gold. "That looks like pyrite," I thought, "But it can't be that, because I know this came from a copper mine, not an iron mine." Today, when I was checking the mineralogy, and looking at pictures of the minerals I didn't recognise--

The thing I thought looked pyrite-y? Was chalcopyrite. CuFeS2. Pyrite but with copper.

I'm still capable of making reasonable geological inferences! Wahey!

(Also at some point I should photograph some of my hand samples, because they are pretty. I'm not sure I can get any good pictures of the peacock ore (aka blue-purple iridescent metallic stuff), because I'll be polishing the peacock-y tarnish off it and it's small. But I should be able to get good pictures of the lime green hand samples, and the ones that look like milk-and-white mint choc ice cream in rock form. ...and maybe I'll even photograph the muddy brown ones. Maybe.)