So, September 16th is National Collect Rocks Day.
Ladies, I’m betting some of us just thought of a good excuse for sending hubby to the jeweler, huh?!? Good thing we’re almost a week away!
Lots of people like collecting rocks. I know I do! Every summer, we spend a week at the lake. Not far from the state park where we camp is a place called Crystal Island. Since I was a kid, I’ve loved going to it and searching for crystals, and each year I beg my husband to take me over with the boat. I suppose I could kayak there, but I’d rather use my energy searching for crystals. The trip never disappoints! I always find some sort of crystal or quartz to add to my growing garden bed of rocks (which, sadly, is looking like the only type of garden my rather blackish thumb is able to manage).
Would you believe it just recently dawned on me, after watching the show for years, that Mr. Slate — full name: Mr. Rockhead Sylvester Nate Oscar George Slate, on the Flintstones cartoon (you know, Fred’s boss at the Bedrock Quarrel and Gravel Company) — probably got his name as a type of geological humor? Yes, I might be a little slow …
The branch of geology that studies rocks and the conditions that form them is called petrology. In it, rocks are classified into three main subdivisions: Sedimentary, Igneous, and Metamorphic.
SEDIMENTARY rock are made up of more than one type of sediment. They are a conglomerate of things such as organic materials, minerals, or other small particles like shells and sand, that have accumulated together and hardened over time. Good examples of sedimentary rock are: limestone, shale, sandstone, breccia, siltstone, one actually called “conglomerate,” and diatomite. You may have heard of diatomaceous earth; it’s a popular organic alternative used as pest control in gardens. It is made from crushed diatomite, which is actually the fossilized remains of diatoms.
When searching for sedimentary specimens for your collection, look for individual grains of sand, or rock that is obviously made up of different types of materials, with perhaps a few pebbles here or there among the whole.
For a fun sedimentary rock activity, find or buy geodes to break open. Geodes can be absolutely breathtaking (the photo at the top of the page is a close-up of the inside of an amethyst geode). Tip: to find one that is mostly hollow inside — and more likely to have crystals or other minerals growing — buy one that feels light for its size. To create two nice halves when you crack it open, gently score the outside of the geode all the way around, before whacking it hard enough to break it in half.
The second division, known as IGNEOUS rock, is made from cooled magma or lava. As lava flows out from the depths of the earth to the surface and meets the cooling air, it solidifies into igneous rock (sometimes also known as magmatic rock). Examples of igneous rock are: basalt, obsidian, granite, pumice, andesite, dacite, scoria, and rhyolite.
The majority of us won’t be able to walk outside and find igneous rock lying about, although you might find your kitchen counter tops are made from it. Don’t fret, though … pumice is one variety of igneous rock that’s likely sold at a store near you, or you can easily find it online.
The last division petrologists study is METAMORPHIC rock. This is rock formed underground, due to heat and pressure. This kind of rock may contain crystals. Examples of metamorphic rock are: marble, quartzite, gneiss (pronounced “nice”), slate, and schist. When identifying metamorphic rock, look for stripes and layers of different-colored rock in your specimen. Crystals will often be arranged in bands.
There are so many neat rocks to collect; it’s a hobby you could never exhaust. My friend Wendy collects heart rocks that her children find for her (she wrote about it in a post from the early days of our blog). They live near a creek known for containing a lot of flint, and her oldest son has found several native arrow heads. My own children love to look for fossils. I have to limit how many they can bring home, though, or they’d fill my van! I’m always willing to compromise by snapping and saving a picture of a cool one, at least until they forget about it. Much easier than getting them to part with a beloved rock they brought home.
How can you explore this hobby with your own children?
- Check out the Science curriculum from our blog sponsor, A Reason For. Your kids will be excited each week by the engaging experiments (including some with rocks). Next month, I’ll be walking through a lesson from Level H here on the blog. When you order A Reason For Science, the supplies you need for 36 weeks of experiments are included in the Materials Kit for each level. You can start collecting specimens today (or buy the Level H curriculum, of course!) to join me next month for an experiment using talc, pyrite, mica, and jasper.
- Did you know there are actually rock painting / hunting Facebook groups, where kids paint rocks and hide them around town like a never-ending Easter egg hunt? When you find one, you take a pic of it, post it on the group Facebook page, and re-hide it somewhere new. This painted rock game has spread all over the globe. Type in “rock hiding group” in your Facebook search engine and see if there is a local one near you; if not, start one!
- Build your own rock collection. Certain kinds of rock may not be easy to find in your area, but you can purchase specimens here and other places online. Have a rock hound in the family already? How about investing in their passion by buying them a rock tumbler, a display case, a specially-designed hammer, or a new book on geology or petrology as their next birthday or Christmas present? Find out if you live close to a place where you can mine crystals, diamonds, or even pan for gold, and consider adding that as a future family outing.
I hope I have shared a little of my love for this hobby, or even fanned the flame of an obsession you once held as a child. If so, make plans to do something about it — and pass on the torch to a new generation. What could be better than helping your kids break free from electronics to explore the beautiful world God has given us? Who knows, you might just raise the world’s next leading petrologist!
Watch for our FREE printable rock sorting game,
coming later this week!
