302-pp21 - Quiz 8 results 1: 1: Wulfenite (79% Wulfenite...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Quiz 8 results 1: 1: Wulfenite (79% Wulfenite (79% ) ) 2: 2: Purpurite Purpurite (79% (79% ) ) 3. 3. Varascite Varascite (79% (79% ) ) 4: 4: Wolframite Wolframite (74% (74% ) ) 5: 5: Barite (53% Barite (53% ) ) 6: 6: Celestine (68% Celestine (68% ) ) Bonus: Bonus: Gibsite Gibsite (32% (32% ) ) Average: 82.6% Highest grade: 108% A: 7 B: 5 C: 3 D: 2 F: 2 GY 302: Crystallography & Mineralogy GY 302: Crystallography & Mineralogy UNIVERSITY OF SOUTH ALABAMA Lecture 21: Inosilicates 1 Pyroxenes and Pyroxenoids Lecture 21: Inosilicates 1 Pyroxenes and Pyroxenoids Class VIII Minerals 1. Sorosilicates 2. Cyclosilicates (3, 4 and 6 fold coordination) Last Time Sorosilicates Mineral Formula System Zoisite Ca 2 Al 3 O(SiO 4 )(Si 2 O 7 )(OH) Orthorhombic Clinozoisite Ca 2 Al 3 O(SiO 4 )(Si 2 O 7 )(OH) Monoclinic Epidote Ca 2 (Al,Fe)Al 2 O(SiO 4 )(Si 2 O 7 )(OH) Monoclinic Allanite (Ca,Ce) 2 (Fe,Fe)Al 2 O(SiO 4 )(Si 2 O 7 )(OH) Monoclinic Lawsonite CaAl 2 SiO 7 (OH) 2 ·H 2 O Orthorhombic Pumpellyite Ca 2 MgAl 2 (SiO 4 )(Si 2 O 7 )(OH)2·H 2 O Monoclinic Vesuvianite (Idocrase) Ca 10 Mg 2 Al 4 (SiO 4 ) 5 (Si 2 O 7 ) 2 (OH) 4 Tetragonal Hemimorphite Zn 4 Si 2 O 7 (OH) 2 ·(H 2 O) Orthorhombic Hemimorphite [Zn 4 Si 2 O 7 (OH) 2 ·H 2 O] Crystal: Orthorhombic Pt. Group: 2mm Habit: massive to mammillary SG: 3.45; H: 5 L: vitreous; Str: white Col: colorless, brown, to grey Clev: perfect [001] Optics: Biaxial (+); bir=0.020 n α =1.61; n β =1.62, n γ =1.736 Sorosilicate Minerals http://webmineral.com/data/Hemimorphite.shtml Named after the hemimorphic nature of the crystals. Cyclosilicates Mineral Formula System Beryl Be 3 Al 2 Si 6 O 18 Hexagonal “Tourmaline” (Na,Ca)(Li,Mg,Al)(Al,Fe,Mn) 6 (BO 3 ) 3 (Si 6 O 18 )(OH) 4 Hexagonal (Trigonal) Cordierite Al 3 (Mg, Fe) 2 (AlSi 5 O 18 ) Orthorhombic Axinite (Ca, Mn, Fe) 3 Al 2 (BO 3 )Si 4 O 12 (OH) Triclinic Dioptase CuSiO 2 (OH) 2 Hexagonal (Trigonal) Silicate rings come in 3, 4 and 6 fold structures. 8-fold structures also occur in nature (e.g., sulfur) Cyclosilicate Minerals 6 fold ring structure Beryl [Be 3 Al 2 Si 6 O 18 ] Crystal: Hexagonal Pt. Group: 6/m 2/m 2/m Habit: euhedral, columnar SG: 2.76; H: 7.5-8 L: vitreous; Str: white Col: blue, yellow, red, green Clev: imperfect Optics: Uniaxial (-); bir=0.004-0.007 n e =1.564; n w =1.568 Cyclosilicate Minerals (6-fold rings)...
View Full Document

This note was uploaded on 02/05/2012 for the course GLY 302 taught by Professor Staff during the Spring '11 term at S. Alabama.

Page1 / 31

302-pp21 - Quiz 8 results 1: 1: Wulfenite (79% Wulfenite...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online