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• Structure in Quarrying Granite
• Mineralogically Granite
• Origin of Granites
• Forms of Igneous Rocks
• Texture in Quarrying Granites
• Mineralogy and Chemistry
• Granite - Conclusion

Mineralogically Granite

Granitic rocks contain essentially quartz, 20-40 vol. percent, alkali feldspar and very commonly mica, and/or muscovite. A number of accessory minerals may be present including apatite, zircon and magnetite. Granites which have been altered by hydrothermal or pneumatolytic action may contain a variety of minerals, e.g., tourmaline, topaz, kaolin etc. Garnet, Coderite and alusite may also be present as contaminants, derived by thermally metamorphosed country rocks, and these contaminants make the granite beautiful. Soda rich granites may contain aegirine and/or riebeckite (Siwana type granite).

Chemically Granite:
Granites characteristically contain a high proportion of silica, often more than 70 percent and relatively high alkalis. Na2O + K2O ranges from 5-12 percent. The MgO is usually less than 1 percent and Calcium. Besides these major oxides, trace elements like Ba, Sr, Li, Rb, Ni, Cr, Co may also be present, but in ppm only. H2O+ may also be present. Granites consisting only of quartz and alkalifeldspar are termed "Alaskites" by decreasing of free quartz granites pass into quartz syenite and thence to syenites.