What do you think sand would look like under a microscope?

If, like me, you guessed it would look like a bunch of light-brown rocks, prepare to be amazed!

http://www.wired.com/design/2014/03/sand-grains-close-unbelievably-cool/

Wow, that's extremely cool.

Looks like Grandma's ribbon candy.

Yep. You can determine where the sand on a beach or in a river was sourced by looking at the makeup of the grains. Our seds prof told a story about where he was approached by the Austin pd, who wanted to know if he could show that the sand they pulled from the cuff of a suspects slacks came from the rio grande rather than the Colorado where he claimed he had been. Turned out the sand was from the Colorado and the suspect was turned loose.

On my first day in Germany, I met my friend's mother in Hamburg. She didn't speak any English and my German wasn't very good, but I remember that the showed me a ziplock bag full of sand. The family had a vacation home on the island of Borkum in the North Sea and I was going to be spending the summer there. She was very proud of her island's sand. I had to agree, it was nice sand.

A lot of sand really does look like small rocks. Apparently I need to load up the kids and the microscope and head to Maui.

I always wanted to see the black sand beaches of Hawaii. Here in NJ our beaches are done up with -very- fine sand

TMI ahead:

The shape and surface finish of sand grains can tell a lot about the environment in which they were deposited. If you examine a sandstone with a microscope, if the grains are round, uniform in size, smooth and frosted, they were deposited in an arid area, most likely a sand dune. If they are clear, jagged and very uniform in size, they were protected from frosting by the cushioning effect of water, and most likely deposited in a gentle, uniform area like the gentle wave action of a seashore. If they are a jumbled up distribution of a variety of sizes, the environment was higher energy. When I was taking optical mineralogy back at the dawn of time, one of our assignments was to collect some sand from near our homes during winter break. Since I lived 10 miles from Lake Ontario, I went there and grabbed a vial full from the beach. When we examined it in the lab when I got back to college, about 90 % of the sand grains were formed of garnets brought in from metamorphic rocks in Canada by the glaciers. Really cool.

End of excruciatingly detailed, useless (but fun) information.

Jim, call me a nerd but I find that quite interesting!

Geology is a really fun science, and one you can use every day as you look around you at the landscape. A general knowledge really makes your national parks even more beautiful. If anyone needs a general distribution science course to fulfill college requirements, you can't go wrong with general geology and general biology.

Spent several of the last few years looking at this stuff and teaching others about it and how to identify what they are seeing. Heck I have even had to cut and mount slices of rock so thin they could be looked at under a microscope (some of those can make the sand look downright boring).

Aren't petrographic scopes cool? Optical was easily my favorite course in school, I spent many, many hours staring down a scope, then spent a couple of years at the USGS making thin sections. Wonderful experience. Then I get sent doing well log analyses, but that's another story.

can these type of images be duplicated with a "standard" microscope ? at what power ?

In reply to Jim Pettengill:

Doing thin sections was cool but you have to get kind I into a zen state while doing it. Come to think of it I have the first thin section I ever did sitting in my desk. It was a piece of basalt we collected on a field trip.

Well logs were never on my favorite subject in geology especially mapping them. I mean it was cool and all just not as cool as some of the other stuff.

EastCoastMojo wrote: Jim, call me a nerd but I find that quite interesting!

Me too, nerd!

I'm going to be spending a week with my little nieces and nephew soon. I think we're going to build an iPhone-powered microscope - and sand is now on the menu. This could be fun.

The beautifully colored images can't be duplicated very easily with a "regular" microscope for reasons that would take too long to explain in detail here. Basically, petrographic microscopes have two polarized light filters, kind of like the ones you have in sunglasses but without the tint. In a pet scope the filters' "preferred vibration directions", i.e. the direction of polarization, are at 90 degrees. Normally this would black out all light and you'd just see black, but most minerals have a crystal structure that "warps" the vibration direction of the light, and this produces what are called interference colors. These colors depend on many things, mostly the crystal structure of the mineral and the thickness of the specimen. If the specimen is a known, standardized thickness, the colors (and other optical properties that we won't get into) can be used to help identify the mineral.

On an artistic level, they sure are purty, especially a nice mineral that displays vivid colors like olivine. I haven't tried it, but I'd bet if you Google thin section, or thin section olivine, you'll turn up some impressive images, and probably a better overall description of the preparation and analysis of thin sections of rock.

For grins, take two pairs of polarized sunglasses, place them on top of each other, look at a cloud, then rotate one pair relative to the other, and you'll see a bit of how this works around the edge of the cloud (usually).

On well logs - definitely not particularly cool, but it paid the bills. I got into geology because I loved the science. How you use it to make a living can be less thrilling. Now that I'm retired, and living in a place where I'm surrounded by world-class glacial features, I'm back in full enjoyment mode.

You haven't lived until you've dissected metal and try to explain why it blew up long before it should have. Hydrogen embrittlement is not the nice ductile cup & cone stuff, it just looks angry.

This metal breaks like ice on a frozen lake.

In reply to Woody:

I have a bag of salt from Bonneville in my desk drawer.

It never stops being cool.