Preliminary: Rocks and Minerals

[butter side up]

Thanks. I was kind of pressed into this event because I was on fossils, and I have no prior experience with R&M other than a week in seventh grade or something, and that was basic.

[gneissisnice]

Almost a mineral but not quite. Can be considered a mineral or a nonmineral. Like opal. Its either poorly crystalline or amorphous.

Right. The most defining feature of a mineral is that it has a distinctive repeating molecular structure. Opal is one exception, since it's basically quartz with water in it; the water is sort of randomly placed within the structure, preventing it from having a repeating crystal lattice, so it's a mineraloid. Obsidian could be considered one as well; it's got a glassy texture, so it doesn't have a crystal lattice, it's just a bunch of different minerals smushed together without having time to form crystals.

[yogoperson]

Ne ne ne...I was wondering where you could find sites where they explain the rock cycle and such. I find books less... fulfilling.. on explaining how igneous, sedimentary, and metamorphic rocks form. And the library is kinda low on these kind of books too.

[Cheesy Pie]

Did you knOw that window glass is a viscous liquid? And obsidian is a rock. It's multiple minerals.

[gneissisnice]

Did you knOw that window glass is a viscous liquid? And obsidian is a rock. It's multiple minerals.

The '"glass is a liquid" thing is a myth. And yes, obsidian wouldn't be a mineral in either case since it's a rock, but the point was that it's not even a rock because it lacks minerals (the minerals in it aren't strictly minerals because they have no repeating crystal lattice".

Anyway, here's a brief rundown of the rock cycle, yogo:

Igneous rocks form from magma and lava; it's full of melted minerals that cool over thousands of years. When the magma cools, the minerals crystallize out at different rates, depending on the composition (this is Bowen's Reaction Series). So igneous rocks are just hardened magma.

Metamorphic rocks are rocks that have been changed by extreme heat and pressure.

Sedimentary rocks are rocks that are composed of sediments, or small grains from other rocks that have been broken down.

So each of these can turn into the other. A sedimentary rock can get buried and end up deep below the Earth's surface, where it gets compacted by heat and pressure and gets metamorphosed. Then that metamorphic rock can move even further down until it's melted into magma. Then it hardens into an igneous rock. Then that igneous rock might uplift to the surface, where it's eroded into particles that get compacted and cemented together, forming a sedimentary rock.

Hope that helps.

[Cheesy Pie]

When I learned about rocks and minerals, it didn't go into much depth. That's why I'm so naïve about this.

[Mimsie]

I don't recall opal being on the minerals list when I was in 8th grade. Which made me sad, it was my birthstone. Haha, to think, my birthstone is neither a rock nor a true mineral.

]: sad.

[gneissisnice]

I don't recall opal being on the minerals list when I was in 8th grade. Which made me sad, it was my birthstone. Haha, to think, my birthstone is neither a rock nor a true mineral.

]: sad.

Opal was on the list, I just checked my old Rocks and Mineral binder (I just found it the other day), and I have a page on opal.

And aww, mineraloids are just as cool as minerals!

[prelude to death]

I don't recall opal being on the minerals list when I was in 8th grade. Which made me sad, it was my birthstone. Haha, to think, my birthstone is neither a rock nor a true mineral.

]: sad.

Opal was on the list, I just checked my old Rocks and Mineral binder (I just found it the other day), and I have a page on opal.

And aww, mineraloids are just as cool as minerals!

Mineraloids ARE just as cool as minerals, if not better, since they are special. :]

[Cheesy Pie]

Yay first year doing R&M and I get mineraloids!!! Speaking of which, do you guys know of any other mineraloids?