About Quartz
Apparently from the Saxon word querkluftertz, meaning cross-vein ore, which could easily have become condensed to querertz and then to quartz; the idea is supported by the old Cornish name for crystalline silica which means cross-course-spar; in any case the word is from German and of ancient derivation.
Quartz hand-specimen
Formula: SiO2
System: Trigonal
Color: Colorless, Purple, Rose, Red, Black, Yellow, Brown, Green, Blue, Orange, etc.
Lustre: Vitreous
Hardness: 7
Density: 2.65–2.66
System: Trigonal
Color: Colorless, Purple, Rose, Red, Black, Yellow, Brown, Green, Blue, Orange, etc.
Lustre: Vitreous
Hardness: 7
Density: 2.65–2.66
XPL
PPL
Quartz #1 thin section (hFOV 2mm)
XPL
PPL
Quartz #2 thin section (hFOV 2mm)
XPL
PPL
Quartz #3 thin section (hFOV 2mm)
XPL
PPL
Quartz #4 thin section (hFOV 2mm)
XPL
PPL
Quartz #5 thin section (hFOV 2mm)
XPL
PPL
Quartz #6 thin section (hFOV 2mm)
XPL
PPL
Quartz #7 thin section (hFOV 2mm)
XPL
PPL
Quartz #8 thin section (hFOV 2mm)
XPL
PPL
Quartz #9 thin section (hFOV 2mm)
XPL
PPL
Quartz #10 thin section (hFOV 2mm)
XPL
PPL
Quartz #11 thin section (hFOV 2mm)
XPL
PPL
Quartz #12 thin section (hFOV 2mm)
![[thumb]](http://microckscopic.ro/wp-content/uploads/quartz_10_03-1-150x150.jpg)
![[thumb]](http://microckscopic.ro/wp-content/uploads/quartz_7_ond_17-150x150.jpg)
![[thumb]](http://microckscopic.ro/wp-content/uploads/quartz_01-150x150.jpg)
![[thumb]](http://microckscopic.ro/wp-content/uploads/quartz_06-150x150.jpg)
![[thumb]](http://microckscopic.ro/wp-content/uploads/quartz_1_01-1-150x150.jpg)
![[thumb]](http://microckscopic.ro/wp-content/uploads/quartz_1_06-150x150.jpg)
![[thumb]](http://microckscopic.ro/wp-content/uploads/quartz_3_01-1-150x150.jpg)
![[thumb]](http://microckscopic.ro/wp-content/uploads/quartz_4_05-1-150x150.jpg)
![[thumb]](http://microckscopic.ro/wp-content/uploads/quartz_5_02-1-150x150.jpg)
![[thumb]](http://microckscopic.ro/wp-content/uploads/quartz_9_02-1-150x150.jpg)
![[thumb]](http://microckscopic.ro/wp-content/uploads/quartz_8_01-150x150.jpg)
![[thumb]](http://microckscopic.ro/wp-content/uploads/quartz_8_05-150x150.jpg)
Quartz PPL properties
Relief: Low positive
Habit/Form: Typically anhedral granular to highly irregular in igneous and metamorphic rocks. Detrital grains are usually more or less equant.
Color: Colorless, clear (with no alterations); it often contain inclusions
Pleochroism: –
Cleavage: –
Habit/Form: Typically anhedral granular to highly irregular in igneous and metamorphic rocks. Detrital grains are usually more or less equant.
Color: Colorless, clear (with no alterations); it often contain inclusions
Pleochroism: –
Cleavage: –
Quartz XPL properties
Isotropy/Anisotropy: Anisotropic
Interference color: Order I white; quartz is very useful in determining the thickness of any slide in which it occurs.
Extinction angle: –
Twins: Absent
Uniaxial/Biaxial: Uniaxial (+)
Optic axial angle (2V): –
Interference color: Order I white; quartz is very useful in determining the thickness of any slide in which it occurs.
Extinction angle: –
Twins: Absent
Uniaxial/Biaxial: Uniaxial (+)
Optic axial angle (2V): –
Quartz distinguishing features under the microscope
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References
- Deer, W. A., Howie, R. A., & Zussman, J. (2013). An introduction to the rock-forming minerals (pp. 498). Mineralogical Society of Great Britain and Ireland, London.
- mindat.org – The Mineral Database
