Rock Identification Labs

Rock Identification Labs

    The Rock Identification Labs over the last two weeks have been my favorite of all labs this semester. Living in the UP over the last two years has made me look closer at my surroundings... including the rocks. As a result of the information I have gained over the last two weeks, I am now able to take an even further look at the rocks I observe on a day-to-day basis. Similar to the Mineral Identification Labs, the emphasis of these labs were on the process. While identifying rocks is similar to identifying minerals, the processes certainly have their differences. Not to mention, there are three distinct kinds of rocks with different characteristcs to look for in terms of their identification. Below are the components to look for when identifying igneous, sedimentary, and metamorphic rocks as well as my Rock Identification Lab II Answer Key.

Igneous

Specimen

Texture

Colors (Light, Intermediate, Dark)

Dominant Minerals

Rock Name

Answer Key:

8	Rough, almost sharp	Light/Dark grey	Felsic	Rhyolite (Pumice)
9	Smooth, glassy	Black	Mafic	Obsidian
10	Rough, air pockets	Red	Mafic	Tuff (Scoria)
11	Rough, has holes	Grey	Intermediate	Scoria (Basalt)
12	Rough, coarse	Light grey	Intermediate	Andesite
13	Rough, can see crystals	Pink	Felsic	Granite
14	Rough, coarse, sandy	Light grey	Felsic	Rhyolite

Sedimentary

Specimen

Detrital or Chemical

Texture (Grain Size)

Composition

Rock Name

Answer Key:

23	Detrital	Very small, grains of sand	Appears like sand	Siltstone (Conglomerate)
24	Detrital	Very small, sandy	Red/pink, sandy	Sandstone
25	Detrital	Very small, sandy	Lighter pink, sandy	Sandstone
26	Detrital	Smooth, extremely fine grains	Light grey, very fine sand	Shale
27	Detrital	Smooth, extremely fine grains	Black, very fine sand	Shale
28	Detrital	Rough, relatively large grains	Angular fragments	Breccia (Calcareous Tufa)
29	Chemical	Coarse, crystalline	Crystals	Rock Gypsum (Limestone)

Metamorphic

Specimen

Foliated or  Non-foliated

Texture (Grain Size)

Composition (If identifiable)

Rock Name

Answer Key:

15	foliated	medium to coarse	greenish	serpentine
16	non-foliated	fine	n/a	slate
17	foliated	medium to coarse	crystals	limestone (Quartzite)
18	non-foliated	medium to coarse	crystals	sandstone (Gneiss)
19	non-foliated	fine	n/a	dolostone (Tale Schist)
20	foliated	medium to coarse	banding	schist
21	non-foliated	medium to coarse	crystals	quartz (Marble)
22	foliated	fine	n/a	bituminous coal (Anthracite)

Additional identification guides: