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Browse Items (2 total)
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Quartz
Formula
SiO2
Structure
Framework silicate
Crystal System
Crystal system: trigonal (+)
Physical Properties
Colour in hand specimen: colourless Lustre: vitreous Pleochroism: none Cleavage: none Hardness: 7
Optical Properties
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Plagioclase feldspar
Formula
Na[AlSi3O8] – Ca[Al2Si2O8]
Structure
Framework silicate
Crystal System
Crystal system: triclinic (+) (-)
Physical Properties
Colour in hand specimen: white Cleavage: two at 90° Hardness: 6-6.5
Optical Properties
Colour in…