Problem Set # 7
                                                                                Silicates
  
 1.  Using the general silicate formula, XmYn(ZpOq)wr, match each appropriate element or element grouping
     and subscript in each mineral formula below with that of each letter or number in the general formula.

     a. Be3Al2Si6O18
     b. CaAl2Si2O7(OH)2

 2.  Match the subclass of silicate with the mineral formula. 
_______     1. CaSiO3 a. nesosilicate
_______     2. KMg3AlSi3O10(OH)2 b. sorosilicate
_______     3. (Mg,Fe)3(Al,Si)4O10(OH)2 c. cyclosilicate
_______     4. Zn4Si2O7(OH)2.H2O d. inosilicate (single chain)
_______     5. CaAl2Si7O18.6H2O e. inosilicate (double chain)
_______     6. (Mg,Fe)7Si8O22(OH)2 f. phyllosilicate
_______     7. Mg3Al2Si3O12 g. tectosilicates
_______     8. LiAlSi2O6 (Al = CN with O of  6)
     
 3.  Match the columns below

_______    1. K-feldspar group a.  nesosilicate
_______    2. mica group b. sorosilicate
_______    3. amphibole group c. cyclosilicate
_______    4. pyroxene group d. inosilicate (single chain)
_______    5. garnet group e. inosilicate (double chain)
_______    6. plagioclase feldspar f. phyllosilicate
    g. tectosilicate

 4. Match the columns below

_______    1. K-feldspar group a. isomorphic group
_______    2. enstatite-ferrosilite b. polymorphic group
_______    3. pyroxene group c. solid solution series
_______    4. amphibole group d. other or chemical group
   
 5. Fill in the mineral name or word which best matches the statement below

__________________a.  the group of tectosilicate subclass displaying a water softening property  
__________________b.  the mineral group whose minerals often display a dodecahedron form of crystal
__________________c.  the plagioclase mineral often displaying iridescence
__________________d.  the silicate subclass with mineral formulas displaying a p:q of 2:7
__________________e.  the inosilicate group of minerals displaying a lack of (OH)x in the formula
__________________f.  the name of the deep green gemstone variety of beryl
__________________g. the name of the most common amphibole mineral
__________________h. the red-pink variety of tourmaline


 6.  Explain why or show how an O in a silicate subclass other than the neso-silicates can form a bond with 
     other element polyhedra if 2 tetrahedra of Z elements (referring to the general formula) are coordinated 
      with that O.  An example is how can a K polyhedron with an 8 CN with O attach with a common O 
      shared by 2 Z tetrahedra to form the mineral, orthoclase?.


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