Podcast
Questions and Answers
What is a characteristic feature of polytypes?
What is a characteristic feature of polytypes?
- Change in symmetry and environment of ions within sheets
- Change in the hardness of the mineral
- Change in the chemical composition of the mineral
- Change in crystallographic system and/or Bravais type of unit cell (correct)
Why are most micas monoclinic rather than hexagonal?
Why are most micas monoclinic rather than hexagonal?
- Because they have a monoclinic crystal structure
- Because their c axis is parallel to the sheets
- Because they have a hexagonal crystal structure
- Because their c axis is inclined relative to the sheets (correct)
What is the likely composition of the garnet replaced by chlorite in a pseudomorph?
What is the likely composition of the garnet replaced by chlorite in a pseudomorph?
- Ca3Al2(SiO4)3
- CaAl2(Si2O7)(SiO4)(O,OH)2
- Fe3Al2(SiO4)3 (correct)
- Mn3Al2(SiO4)3
What is the difference between 'brittle' micas and true micas?
What is the difference between 'brittle' micas and true micas?
What is the result of substituting Al3+ for Si4+ in tetrahedra?
What is the result of substituting Al3+ for Si4+ in tetrahedra?
What is the characteristic feature of chlorite minerals?
What is the characteristic feature of chlorite minerals?
What is the characteristic that allows phyllosilicates to exchange ions with fluids in their surroundings?
What is the characteristic that allows phyllosilicates to exchange ions with fluids in their surroundings?
What is the T:O ratio in the tetrahedral sheet of phyllosilicates?
What is the T:O ratio in the tetrahedral sheet of phyllosilicates?
What type of sheet is identical to the basic structural unit of the mineral Mg(OH)2?
What type of sheet is identical to the basic structural unit of the mineral Mg(OH)2?
What is the valence of the metallic cations filling the octahedral sheet in dioctahedral phyllosilicates?
What is the valence of the metallic cations filling the octahedral sheet in dioctahedral phyllosilicates?
What is the characteristic that makes phyllosilicates versatile in everyday products?
What is the characteristic that makes phyllosilicates versatile in everyday products?
What is the difference between dioctahedral and trioctahedral phyllosilicates?
What is the difference between dioctahedral and trioctahedral phyllosilicates?
What is the main difference between the structure of dioctahedral muscovite and trioctahedral lepidolite?
What is the main difference between the structure of dioctahedral muscovite and trioctahedral lepidolite?
What is the name given to fine-grained muscovite?
What is the name given to fine-grained muscovite?
What is the significance of polytypism in phyllosilicates?
What is the significance of polytypism in phyllosilicates?
What is the significance of the pseudohexagonal habit of biotite?
What is the significance of the pseudohexagonal habit of biotite?
What is the main difference between muscovite and illite?
What is the main difference between muscovite and illite?
What is the use of muscovite and Fe-free phlogopite in electrical devices?
What is the use of muscovite and Fe-free phlogopite in electrical devices?
What is the characteristic of the octahedral sheet in phyllosilicates?
What is the characteristic of the octahedral sheet in phyllosilicates?
Which type of phyllosilicate has a valence of 2+ for the metallic cations in the octahedral sheet?
Which type of phyllosilicate has a valence of 2+ for the metallic cations in the octahedral sheet?
What is the name of the mineral that has a similar structure to the 'brucite' sheet?
What is the name of the mineral that has a similar structure to the 'brucite' sheet?
Which of the following minerals is not a type of phyllosilicate?
Which of the following minerals is not a type of phyllosilicate?
What is the term for the subdivision of phyllosilicates based on the valence of the metallic cations in the octahedral sheet?
What is the term for the subdivision of phyllosilicates based on the valence of the metallic cations in the octahedral sheet?
What is the name of the mineral that has a similar structure to the 'gibbsite' sheet?
What is the name of the mineral that has a similar structure to the 'gibbsite' sheet?
What is the name of the mineral group that includes antigorite, lizardite, and chrysotile?
What is the name of the mineral group that includes antigorite, lizardite, and chrysotile?
What is the characteristic feature of the structure of antigorite?
What is the characteristic feature of the structure of antigorite?
What is the name of the mineral that is often referred to as 'blue asbestos'?
What is the name of the mineral that is often referred to as 'blue asbestos'?
What is the composition of the minerals in the serpentine group?
What is the composition of the minerals in the serpentine group?
What is the term for rocks that are made up mostly of minerals from the serpentine or clay group?
What is the term for rocks that are made up mostly of minerals from the serpentine or clay group?
What is the characteristic feature of the structure of chrysotile?
What is the characteristic feature of the structure of chrysotile?
What is the structural characteristic of lepidolite that differs among its three polytypes?
What is the structural characteristic of lepidolite that differs among its three polytypes?
What is the mineral that forms as an alteration mineral in silica-poor rocks, often with corundum?
What is the mineral that forms as an alteration mineral in silica-poor rocks, often with corundum?
What is the result of substituting Al3+ for Si4+ in tetrahedra, with charge balance maintained by coupling with another cation?
What is the result of substituting Al3+ for Si4+ in tetrahedra, with charge balance maintained by coupling with another cation?
What is the characteristic of the chlorite group that distinguishes it from other minerals?
What is the characteristic of the chlorite group that distinguishes it from other minerals?
Which mineral is a flexible muscovite with a specific chemical composition?
Which mineral is a flexible muscovite with a specific chemical composition?
What is the significance of polytypes in minerals with definite sheet structures?
What is the significance of polytypes in minerals with definite sheet structures?