GEOL-1021EL Lecture Notes - Lecture 4: Radiolaria, Calcite, Hematite
16 Jun 2018
School
Department
Course
Professor
GEOL-1021
October 15th, 2017
October 19th, 2017
Earth Materials
What are Minerals?
•Minerals are the building blocks of rocks
•Naturally occurring
•solid
•crystalline substance
•generally inorganic
•specific chemical composition (does not have to be fixed or pure within certain limits)
•Exceptions to inorganic rule:
1. calcite: in shells/foraminifera
2. Silica in radiolaria
3. Apatite in teeth
•Reason: these substances can also be produced by geological processes
•Mineral or not?
•Ice?
•Hell yeah, it’s a mineral. Fulfills all characteristics of the definition.
•Major component of the crust of both Jupiter and Saturn.
•Has a distinct atomic arrangement
•Coal?
•No, bitch, it’s a rock containing carbon in a variety of forms- some non-crystalline, as
well as other impurities. Elemental carbon forms two distinct minerals: graphite and
diamonds. Carbon is also a key component in a family of minerals: carbonates.
•Amber?
•Not a mineral. Non crystalline and only of organic origin.
How minerals form
•Crystallization
•Atoms come together from a solution in specific proportions to form orderly
arrangements
•the solution can be water based (precipitation due to cooling of heroes fluids/types of
sedimentary rocks)
•Recrystillization
•from pre existing minerals upon changes in temperature and pressure
•increase
Main Mineral Groups
•Silicates
•Isolated silica tetrahedra
•Single chain linkages (share two oxygens)
•double chain linkages (three of two oxygens)
•sheet linkages (share three Oxygens)
•frameworks (share four oxygens)
•Carbonates- calcite
•oxides- hematite
