Environmental Engineering Reference
In-Depth Information
TABLE 6.13
Susceptibility to Weathering of Common Rock-Forming Silicate Minerals and their Occurrence in Various Igneous Rocks
a
Rock Types
Susceptibility
Dark Minerals
Light Minerals
Volcanic
Intrusive
Sequence of
to Weathering
Crystallization
Least resistant
Olivine (Mg,Fe)
2
SiO
4
Calcic plagioclase
Early
(anorthite) CaAl
2
Si
2
O
8
Augite
Calcic
plagioclase
Basalt
Gabbro
(Ca,Mg,Fe,Al)
2
(Al,Si)
2
O
6
(OH)
2
(labradorite) with sodium
Hornblende
Sodium plagioclase with
Andesite
Diorite
(Ca,Na,Fe,Mg,Al)
7
(Al,Si)
8
O
22
(OH)
2
calcium (andesine,
oligoclase)
Sodium plagioclase (albite)
Latile
Monzonite
NaAlSi
3
O
8
Biotite (dark mica)
Potash feldspar (orthoclase,
Rhyolite
Granite
K(Mg,Fe)
3
(Al,Si
3
)O
10
(OH,F)
2
microcline) KAl
2
Si
3
O
8
Muscovite (white mica)
KAl
2
(Al,Si
3
)O
10
(OH,F)
2
Most resistant
Quartz, SiO
2
Late
a
After Hunt, C.B.,
Geology of Soils
, W.H. Freeman and Company, San Francisco, 1972. Reprinted with permission of W. H. Freeman and Co. Adapted from Goldrich (1938).
