Yes, I mean actual diamonds. I cut rocks with diamonds. Be jealous.
Ok, so they’re REALLY tiny (microscopic, even), and they’re synthetic, so it sounds a lot cooler than it actually is.
Oh, who am I kidding, cutting rocks is one of the best things about being a geologist. Especially when you’re cutting sedimentary rocks with a diamond rock saw – it’s like slicing butter with a hot knife. If someone ever asks you if you want to try cutting a rock, just say yes.
Last Friday I got to cut some rocks as part of my thesis work. I’m going to attempt to explain my thesis project in non-geologist terms in a later post, but right now I just want to brag about cutting rocks and feeling a little bit like a god while doing so. This particular batch of rocks were all from a fresh rock core (someone drilled a tube into the subsurface and pulled out a cylinder of rock – essentially). The core was also thankfully already sliced in half. You might imagine that flat edges would make rock cutting much easier, and you’d be right.
This is what the rocks looked like before I started slicing them, except for the 2 at the top. The goal is to cut a thin section “blank.” They go by many names (billet, chip…), but the piece you cut before it gets shaved down enough that light can pass through it under a microscope. They’re roughly 1″ x 1 & 7/8″ and about half an inch thick. Then we send them off to a lab where everything is standardized and we get a bunch of perfect thin sections returned like magic. And then I have to count 70,000 individual grains, among many other things. But I’m getting ahead of myself.
The rock saw! It’s basically stationary, and you put your rock on the rack, and move the rack under the blade. That chip sitting on it is a typical thin section blank. Fun fact: it’s pretty difficult to cut yourself on this blade, even though it’s designed to cut rocks. It’s actually pretty blunt – about 1/16″ thick. I meant, don’t get your finger trapped between the rock and the blade, but you could probably hold your finger right on the blade as it spins and it wouldn’t cut you.
Look! I’m doing science! Literally just sliding the rock into the blade, and it just cuts. You gotta go slow, so you don’t fracture the rock or damage the blade. But not THAT slow. At least, not with sedimentary rocks. We were able to cut about 15 samples in about 3 hours – and that includes refilling water buckets and labeling everything. I have to cut about 85 more though… going to be a busy few weeks.
In the end, this is what we had left. I failed to take a photo of any of the actually blanks, because… I have no excuse, it just didn’t happen.
Honestly, I am just really excited to get this part done. Microscopes are fun. Probably I’ll change my mind about this after I spend many hours staring down into them, but rocks look really cool in thin section. I’ll hopefully post some photos of that when I get around to that process. My project is mostly a sedimentary petrology deal (petrology = looking at rocks under a microscope and identifying minerals and figuring out where the sediment came from), and I am just really anxious to get to the data collection part. Collecting and preparing samples is only fun for the first few days, in my opinion.
Then there are the big cabinets in the lab that just say “ACID” on them in giant red letters…