Show and Tell – Old Skool

Today’s Kickin’ it Old Skool Blog-a-thon we’re challenged to do a little show-and-tell, a’la kindergarten.

I wasn’t sure what to post about, then I remembered that I need to write a (separate) blog post about Bowen’s Reaction Series, which is a geology thing that explains which minerals will be found together in igneous rocks. I’ll write the post later.

But what it means is that I need to take some pictures of minerals…

So, let me show you pictures of the most common minerals on Earth! If you know these few minerals, you’ll know a lot about petrology (the study of rocks and their components).

The mineral orthoclase. Also called potassium feldspar or K-spar.

The mineral orthoclase. Also called potassium feldspar or K-spar.

Quartz. This is one mineral almost everyone has heard of!

Quartz. This is one mineral almost everyone has heard of!

Muscovite. A type of mica that is fairly light in color.

Muscovite. A type of mica that is fairly light in color.

This is biotite, another type of mica that is dark in color.

This is biotite, another type of mica that is dark in color.

This mineral is part of the group of minearls called amphiboles. Specifically, this is hornblende.

This mineral is part of the group of minearls called amphiboles. Specifically, this is hornblende.

This mineral is part of the pyroxene group of minerals. It is called augite and looks a lot like hornblende.

This mineral is part of the pyroxene group of minerals. It is called augite and looks a lot like hornblende.

This mineral is called olivine (actually this is a rock, made up of olivine crystals). It's easy to recognise because of its pimento olive color.

This mineral is called olivine (actually this is a rock, made up of olivine crystals). It’s easy to recognise because of its pimento olive color.

The next four minerals are all members of the plagioclase group of minerals. They differ slightly in chemical composition, which makes them different colors. They are all similar in that they have striations – little thin parallel lines – on their crystal faces. See if you can see them.

At the light end of the plagioclase scale is the mineral albite. Its rich in the element sodium.

At the light end of the plagioclase scale is the mineral albite. Its rich in the element sodium.

Slightly darker plagioglase.

Slightly darker plagioglase.

This is what happens when plagioclase has quite a bit of calcium and not so much sodium.

This is what happens when plagioclase has quite a bit of calcium and not so much sodium. This type of plagioclase has the name anorthite.

At the dark end of the plagioclase scale is this mineral. It has lots of calcium and little sodium.

At the dark end of the plagioclase scale is this mineral. It has lots of calcium and little sodium.

Now, go out there and look at rocks. Especially nicely polished rocks like granite table tops. See if you can identify any of these minerals (and stay tuned for the upcoming post explaining Bowen’s Reaction Series).

15 thoughts on “Show and Tell – Old Skool

  1. I love rocks. I love rocks so much that people bring me rocks that they think I might like. I also have quite a collection of countertop samples just because I thought they were so pretty. My kitchen countertop is Soapstone. But I still pick up free samples of granite and marble because I like them so much.

  2. Love rocks and stones! I have some in shadow boxes that I have not been able to identify. Would love to have you close. Thanks for sharing!

  3. I love to look at rocks. As a child, we had so many in the fields. There was a pile that I loved to play on. The rocks that could be used as a blackboard were especially interesting to me because I could draw on them. They are purplish rocks. I’m pretty sure you would know what they are (but I don’t).

  4. These are some of the teaching specimens I have sitting around in the laboratory. Some of them are pretty nice, which surprizes me after who knows how many years of grubby fingers!

  5. My guess would be slate. The original chalkboards were made of slate, as were pool tables. There still are slate roofs on houses from time-to-time.

  6. So glad to hear that science was your concentration and that you’re working in the geosciences! I can’t get enough of geology, myself, and I don’t think there’s enough out there!

  7. I have boxes of rocks in one of our outbuildings. My family always hates it when I move because the rocks are so heavy! I get brought rocks too, and have little piles everywhere.

  8. This reminds me about how much I like to help people understand the mysteries of everyday things, like rocks. I should make a regular column of ‘identify this rock’ or something similar. Maybe alternate it with ‘what do you see in this photo I took from an airplane window?’ Which means I need to set up a submissions mailbox for such things. Hmmm. Look for it coming soon….

  9. I didn’t know slate could be purple, but then I found a book Pre-Cambrian Geology in North America in Google Books. It was that simple. Thanks!

  10. Thank you so much you’ve helped me confirm for sure, my favorite mineral to find and grind. The orthoclase (K Spar)

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