|
Geometry
and symmetry of minerals |
. |
The bulk of the matter comprising the earth's crust exists as compounds of |
. |
elements called minerals. There are more than 3,000 naturally
occurring inorganic |
. |
minerals, many of which exist in solid forms of varying composition, not to
mention |
. |
the
countless number of synthetic compounds that have been formulated. |
. |
. |
. |
Conventional mineral classification scheme |
. |
Mineralogists have attempted to bring order to this vast collection of
diverse matter |
by
cross indexing minerals with the chief nonmetal or radical present and the
type of |
structure commonly exhibited by them. Often elements and minerals
grouped in this |
way
are very similar in appearance, behave similarly when treated chemically,
and |
occur under similar geologic conditions. |
The following table is an example of such a classification scheme. In
the left hand |
column the elements and minerals are grouped by the chief non-metal or
radical |
present. In the right hand column each group is subdivided by the type
of structure |
commonly exhibited by the group. The name of the structure is derived
from an |
element or mineral of the subgroup that is most commonly identified with the |
structure or exhibits it most clearly. |
. |
|
|
|
Element/mineral |
Structural type |
Element/mineral |
Structure type |
Native metals |
|
Halides (continued) |
|
Au,Ag,Cu,Pb,Pt,Pd |
gold |
halite group |
|
a-Sn |
diamond |
halite |
halite |
a-Fe |
bcc |
sylvite |
"
" |
Native nonmetals |
|
fluorite |
fluorite |
C (diamond) |
diamond |
Oxides |
|
C (graphite) |
hp |
periclase group |
|
Sulfides |
|
periclase |
halite |
cinnabar |
zincblende |
bunsenite |
"
" |
greenocite |
wurtzite |
manganosite |
"
" |
galena group |
|
zincite group |
|
galena |
halite |
zincite |
wurtzite |
altaite |
" " |
bromellite |
"
" |
clausthalite |
" " |
cuprite |
cuprite |
albandite |
" " |
corundum group |
|
oldhamite |
" " |
corundum |
corundum |
sphalerite group |
|
hematite |
" " |
zincblende |
zincblende |
ilmenite |
" " |
metacinnabar |
" " |
spinel group |
|
tiemannite |
" " |
spinel |
spinel |
coloradoite |
" " |
gahnite |
"
" |
molybdenite group |
|
hercynite |
"
" |
molybdenite |
molybdenite |
magnetite |
spinel
(inverse) |
tunstenite |
" " |
rutile group |
|
argentite group |
|
rutile |
rutile |
argentite |
anti-flourite |
pyrolusite |
" " |
chalcopyrite group |
|
cassiterite |
" " |
chalcopyrite |
zincblende |
plattnerite |
" " |
stannite |
" " |
urraninite group |
|
niccolite group |
|
urraninite |
flourite |
niccolite |
niccolite |
thorianite |
"
" |
pyrrhotite |
" " (def.) |
diaspore group |
|
breithuptite |
" " |
diaspore |
diaspore |
skutterudite group |
|
goethite |
" " |
skutterudite |
|
brucite group |
|
Sulfosalts |
|
brucite |
CdI2 |
enargite group |
|
pyrochroite |
" |
enargite |
enargite |
portlandite |
" |
Halides |
|
boehmite |
|
nantokite |
zincblende |
lepidocrocite |
boehmite |
marshite |
" " |
litharge |
PbO |
miersite |
" " |
|
|
|
|
Table 3
- Conventional mineral classification system |
|
Back to
Knowhere |
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Page
38 - Structure matters - Minerals |
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