• Feldspars and Quartz

General Feldspar Group Info

• Feldspar Compositions
• Feldspar Group Structure
• Al ordering in Feldspars - See also Table 12.3
• Feldspar Twinning

Plagioclase

• Plagioclase Properties - see Nesse p. 215
• Plagioclase in Thin Section - another view
• Plagioclase Compositional Variation and Optical Properties
• Associated Minerals:
  • Sericite as an alteration mineral

K-Feldspar

• K-Feldspar Properties - see Nesse p. 220
• K-Feldspar in Hand Sample and Thin Section - another view
• K-Feldspar Compositional Variation and Optical Properties
• Associated Minerals:
  • Sericite as an alteration mineral

Quartz

• SiO₂ Phase Diagram
• Quartz Properties - see Nesse p. 202
• Quartz Crystal Structure
• Quartz in Hand Sample and Thin Section - another view