Are rocks broken down into various categories?

Question

I think there are the three main kinds of rocks in the beginning, but what about after that?

I was thinking that maybe they have something like the animal kingdom, so many families, etc.

Answer 1

The three main categories are igneous, metamorphic, and sedimentary.

igneous are volcanic rocks, like granites and basalts and are made up of minerals that had time to crystallize out of the magma before being erupted.
an igneous rock with big crystals had more time in the magma, because big crystals need lots of time to form.
a volcanic glass, for example obsidian, had no time to form crystals, as it hardened upon being erupted out of the volcano.

sedimentary rocks are those that are made up of sediments. examples include limestone and sandstone. first the sediments are laid down, like dirt, and are eventually lithified by pressure, i.e. being buried by more sediments. different sedimentary environments create different rocks. limestones are formed in shallow seas where critters with shells made of calcium carbonate die and allow their shells to fall to the ocean floor. sandstones do not need water to form. they can form at deserts or beaches. it is hard to tell the difference between a rock formed at a beach versus a desert, but there are ways.

metamorphic rocks can be igneous or sedimentary to begin with. once the rock is formed, it is changed by increased pressure (i.e. gets reburied deeper into the earth's crust) and temperature (deeper means higher temperature) to form a new rock. when limestone is buried very deep, it condenses into marble.

those main parts are then broken down based on characteristics of an individual rock. if a rock is made up of other smaller, rounded rocks that have been cemented together, it is called a conglomerate. if those rocks that are cemented together are sharp and not rounded, the rock is a breccia and not a conglomerate.

about.com has a good section on geology that can answer your questions more thoroughly than i can here.
hope that helps!

Answer 2

There truly are only three basic types of rocks. However, within those types there are a truly dizzying array of subtypes. However, you can't really draw distinctions across categories.

For instance, genus Megaponera and genus Homo are unrelated, but they can still be back-grouped into Kingdom Animalia. That won't work for rocks; one simply cannot use the same terms to say, describe igneous rocks and sedimentary ones, or sedimentary and metamorphic, etc. However, *within* those categories, one can distinguish a great deal.

Answer 3

Yes, they are divided into the fololowing...
Igneous
Sedimentary
Metamorphic

Metamorphic...Glassy (External cooling) Then Grainy (Internal cooling with a list of grain sizes)
Sedimentary... Clastic or Fragmental
Igenous... I believe Vesicular or non Vesicular, though that could be for Metamorphic

It really doesn't correspond with the animal kingdom but it is a reock classifiying chart in the least.

Answer 4

Well, yes. After the three main categories, some scientists may want to seperate the rocks more by the elements they are made out of. So it would be Elements/Chemcial Groups if you wanted to go more detailed.

Answer 5

Yes,

I believe 1. boulder, 2. rock, 3. pebble, 4 sand.....or something of that nature.

Answer 6

Igneous, sedimentary and metamorphic

Answer 7

igneous rock (ex: pumice, quartz, granite)
sedimentary rock (ex: sandstone, limestone)
metamorphic rock (ex: marble, slate)

Answer 8

They already are: igneous, sedimentary and metamorphic.

Read this to learn more about them:
http://jersey.uoregon.edu/~mstrick/AskGeoMan/geoQuerry13.html

Answer 9

They do.I just don't know what they are

Answer 10

idk