Name_______________________
Reference Table Activity: Igneous Rocks
Using your knowledge of rock properties and the “Scheme for Igneous Rock Identification”
From the ESRT answer the following questions:
1)_________________According to the ESRT, as you move to the right from granite to gabbro,
the general color of the minerals making up the rock become…………
2)_________________According to the ESRT, as you move downward from Basaltic glass to
Gabbro the texture of the of the rock becomes (finer/coarser).
3)_________________According to the ESRT, a fine textured, light colored igneous rock would
best be called (granite, pegmatite, rhyolite, diorite).
4)_________________Which of the following rocks from the chart would probably be densest?
(Granite, andesite, scoria, pumice, diorite)
5)_________________Which of the following rocks would probably be made up of the largest
mineral grains? (granite, scoria, pumice, basalt)
6) According to the ESRT, the characteristics of rocks that contain Potassium feldspar and quartz are:
________________________color
________________________density
________________________composition
7) According to the ESRT, the characteristics of rocks that contain Pyroxene and olivine are:
_______________________color
_______________________density
_______________________composition
8) ________________According to the ESRT, very coarse grained intrusive rocks are called…..
9)________________According to the ESRT, which of the following rocks must contain quartz?
(Gabbro, diorite, andesite, rhyolite)
10)_______________According to the ESRT, which of the following rocks must contain
Pyroxene? (granite, diorite, basalt, obsidian)
11)______________ According to the ESRT, as granite becomes darker in color, the amount of plagioclase
feldspar content generally (increases, decreases, remains the same)
12)______________A fine grained igneous rock contains plagioclase feldspars and pyroxene but no quartz.
The rock most likely is (granite, rhyolite, diorite, gabbro, basalt)
13)______________A coarse grained igneous rock contains Plagioclase feldspar, biotite mica, but no olivine.
The rock is most likely (gabbro, rhyolite, andesite, granite)
14)______________A glassy textured igneous rock contains approximately twice as much Amphibole as biotite
and over 50% plagioclase feldspar. This rock is most likely (granite, gabbro, obsidian,
diorite basalt)
15)______________Name an igneous rock which has crystallized deep within the earth’s crust which has the
following approximate mineral composition:
Plagioclase feldspar 20%
Quartz 40%
Potassium Feldspar 20%
Biotite Mica 10%
16)______________Name an igneous rock which has crystallized at or near the earth’s surface which has the
following approximate mineral composition:
Pyroxene 60%
Plagioclase Feldspar 30%
Olivine 5%
Amphibole 5%
17)______________A vesicular, glassy textured igneous rock made of mostly Pyroxene and Plagioclase
Feldspar would most likely be called….