Name: Date: 09/22/18 EESC 1010 The Dynamic Earth Fall 2018 Brooklyn College Home
ID: 154074 • Letter: N
Question
Name: Date: 09/22/18 EESC 1010 The Dynamic Earth Fall 2018 Brooklyn College Homework #2 Minerals 2 Pages 1-12, Lecture Notes Due 9/25/2018 at 10:30 am Directions: Answer the following questions using complete sentences. (5) 1. There are 6 common nonsilicate mineral types. List three of them and provide an example. The three nonsilicat mineral types are Oxides, for example aluminum oxide. Another one is Sulfides, for example iron disulfide; and lastly Carbonates, for example calcium carbonate. (6) 2. What do all silicates have in common? what are the 5 structures that silicates are arranged in? - All silicate minerals have the same fundamental building block; silicon-oxygen tetrahedron. There are 5 structures that silicates are arranged in; Cvclosilicates, Single chain inosilicates, Double chain inosilicates, Phyllosilicates, Tectosilicates. _(1) 3. What is the difference between biotite and muscovite chemically (Lecture Il Notes)? --(1) 4. what is the difference between orthoclase and plagioclase chemically (Lecture Notes)?Explanation / Answer
3. What is the difference between biotite and muscovite chemically?
Answer: Chemical composition of biotite: K(Mg,Fe)3AlSi3O10(OH)2
Chemical composition of muscovite: KAl2(AlSi3O10)(OH,F,Cl)2
So, biotite is magnesium-iron rich mica or, black mica and muscovite is aluminium rich mica or, white mica. The change in ratio of magnesium and iron in biotite can give different composition and different minerals, like Phlogopite is pure magnesium biotite and annite is pure iron biotite. But, in case of muscovite, this type of range in composition is not found. This is the difference between biotite and muscovite chemically.
4. What is the difference between orthoclase and plagioclase chemically?
Answer: Chemical composition of orthoclase- KAlSi3O8
Chemical composition of plagioclase feldspar - NaAlSi3O8 – CaAl2Si2O8. So, plagioclase feldspars have a range of composition. Plagioclase feldspar is a group of feldspars formed by solid solution of pure albite- NaAlSi3O8 to pure anorthite- CaAl2Si2O8. In the series of plagioclase we get a series of minerals like- albite, oligoclase, andesine, labradorite, bytownite, anorthite.
So, orthoclase is potash rich feldspar, but plagioclase feldspar is either soda rich or calcium rich or both are mixed.
Another difference between orthoclase and plagioclase is- when weathering occurs, then orthoclase alters into kaolinite and plagioclase feldspars alter into sericite.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.