Mineral Set 3 Questions Flashcards
How does Kaolinite form?
Kaolinite forms as a SECONDARY mineral of Aluminum Silicates by weathering and/or hydrothermal alteration.
What is Bentonite? What is it’s main Clay Constituent?
Bentonite is altered volcanic ash. It’s main clay constituent is Smectite or “Swelling Clay”.
Antigorite and Chrysotile are Polymorphs in what mineral group?
They are polymorphs of serpentine - Mg3Si2O5(OH)4
What chemical compound is required for forsterite to alter serpentine?
Olivine = (Mg,Fe)2SiO4
Forsterite = Mg-Rich = Mg2SiO4
Adding H2O will alter serpentine.
Forsterite + Water = Serpentine + Brucite
Which mineral, Talc or Serpentine, has a higher MgSi2O5 ratio?
Serpentine.
Serpentine = Mg3Si2O5(OH)4
Talc = Mg3Si4O10(OH)2
What is Paragonite? To what degree does it have solid solution with muscovite at room temp?
Paragonite is a sodic muscovite. Paragonite has Na, Muscovite has K.
It does not have a solid solution at room temp with muscovite. However, solid solution is limited to no more than ~10% Na in Muscovite, and ~20% K in Paragonite.
In the discussion of Phyllosilicates, what is a “book”?
A book is a large crystal of Mica, while the individual sheets of cleavage represent the pages of the book.
What is phlogopite? How does it compare chemically to Biotite?
Phlogopite is an end-member of biotite.
Phlogopite = KMg3AlSi3O10(OH)2
Biotite = K(Mg,Fe)3AlSi3O10(OH)
What metamorphic grade of facies does chlorite commonly indicate?
Greenschist grade Metamorphism.
What igneous minerals alter to chlorite?
Pyroxene, amphiboles, biotite, and garnet.
What is the environment of occurrence of Lepidolite?
Lithium Bearing pegmatites.
What environment does Glauconite usually form in?
Clastic sediments within marine environments.
What is the habit presented by Prehnite sample?
Globular, radiating sheaflike aggregates.
