Dichotomous Key
|
1 |
A Fizzes when a drop of dilute hydrochloric acid is placed on it |
13 |
|
|
B Does not fizz when a drop of dilute hydrochloric acid is placed on it |
2 |
||
|
2 |
A Crystals can be seen without a lens |
3 |
|
|
B Crystals cannot be seen without a lens |
6 |
||
|
3 |
A Made up of particles smaller than 2 mm |
4 |
|
|
B Made up of particles larger than 2 mm |
conglomerate |
||
|
4 |
A Grains look like sand easily scratched off |
sandstone |
|
|
B Grains not like sand cannot be scratched off |
5 |
||
|
5 |
A One colour usually white large crystal |
13 |
|
|
B Made up of several different colours |
granite |
||
|
6 |
A Powder can be scratched off |
7 |
|
|
B Powder cannot easily be scratched off |
11 |
||
|
7 |
A Soft and has many holes |
pmice |
|
|
B Does not have holes |
8 |
||
|
8 |
A Dark, burns easily, may be shiny |
9 |
|
|
B Dull does not burn |
10 |
||
|
9 |
A Can be scratched with fingernail |
peat |
|
|
B Cannot be scratched with fingernail |
coal |
||
|
10 |
A Thin layers visible |
shale |
|
|
B Not layered |
siltsone |
||
|
11 |
A Dull very fine grains, splits in layers |
slate |
|
|
B Does not split in layers |
12 |
||
|
12 |
A Large crystals |
quartzite |
|
|
B Small crystals |
14 |
||
|
13 |
A Sedimentary rock may contain fossils |
limestoe |
|
|
B Metamorphic rock made of calcite |
marble |
||
|
14 |
A Dark small crystals |
basalt |
|
|
B Small crystals |
gabbro |
Rock Classification
| IGNEOUS | Rocks that have solidified from a molten state.
There are two types of Igneous rocks: Plutonic - Rock from magma rising up from deep under the earth's crust; solidified before it reached the earth's surface. Volcanic - Rock that was originally lava, hot magma that reached the surface of the earth before it hardened. |
plutonic igneous rocks - Granite, Peridotite
volcanic igneous rocks - Obsidian, Basalt, Rhyolite |
| SEDIMENTARY | Rock formed by the accumulation of particles on or near the earth's surface, and compacted down, often under pressure, creating rock layers. | Limestone, Shale, Sandstone, Dolomite, Gypsum, Quartzite, and stones containing fossils |
| METAMORPHIC | Rocks resulting from changes within preexisting rocks, by extreme pressure, temperature, and chemical activity. | Kyanite, Mica, Garnet, Calcite, Quartz, Pyrite, Marble, Gneiss, Schist |