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Id 47
Identification Type Mineral
Name Quartz
Distinguishing Features Low-birefringence
Equant
Description Transparent colorless; equant grains; cleavage absent. Grains larger than ~30um show higher order birefringence colors (dark orange, pink), while smaller grains appear white or gray in cross-polarized light. May appear pitted, or show opaque or reddish coatings visible in plane polarized or reflected light. May be well-rounded where aeolian or fluvial transport contributes. Common mineral in detrital sediments and rock fragments.
Tags silicate
Transparent
Colorless
Low-relief
External Resources Quartz on MinDat
Imposters Feldspar
Quartz and feldspar have similar low-order birefringence colors (white to gray) and regularly co-occur. They can be distinguished from each other by cleavage: feldspar has good cleavage, and quartz has no cleavage. That is, if the grain has a straight edge, it's not quartz.
Images
Unique Identification: Quartz
Site name: Reid Lake
Light type: Plane-Polarized Light
Magnification: not specified
Submitted by: Andy Breckenridge
Notes: quartz, undulose extinction, detrital, glaciolacustrine
Image Tags: none
Unique Identification: Quartz
Site name: Reid Lake
Light type: Cross-Polarized Light
Magnification: not specified
Submitted by: Andy Breckenridge
Notes: quartz, undulose extinction, detrital, glaciolacustrine
Image Tags: none
Unique Identification: Quartz
Site name: not specified
Light type: Plane-Polarized Light
Magnification: 400x
Submitted by: Amy Myrbo
Notes: rounded coarse-grained
Image Tags: none
Unique Identification: Quartz
Site name: not specified
Light type: Cross-Polarized Light
Magnification: 400x
Submitted by: Amy Myrbo
Notes: (larger grain that gives higher order birefringence colors than it should!)
Image Tags: none
Unique Identification: Quartz
Site name: not specified
Light type: Plane-Polarized Light
Magnification: 400x
Submitted by: Amy Myrbo
Notes: stain
Image Tags: none
Unique Identification: Quartz
Site name: not specified
Light type: Cross-Polarized Light
Magnification: 400x
Submitted by: Amy Myrbo
Notes: stain
Image Tags: none
Unique Identification: Quartz
Site name: South Fraserdale, ON
Light type: Plane-Polarized Light
Magnification: not specified
Submitted by: Andy Breckenridge
Notes: quartz, detrital, glaciolacustrine
Image Tags: none
Unique Identification: Quartz
Site name: South Fraserdale, ON
Light type: Cross-Polarized Light
Magnification: not specified
Submitted by: Andy Breckenridge
Notes: quartz, detrital, glaciolacustrine
Image Tags: none
Unique Identification: Quartz
Site name: Arthurs Lake
Light type: Plane-Polarized Light
Magnification: 400
Submitted by: Val Stanley
Notes: Note inclusions in quartz, likely rutilated
Image Tags: rutilated
Unique Identification: Quartz
Site name: St. Louis River
Light type: Plane-Polarized Light
Magnification: 400
Submitted by: Val Stanley
Notes: Note inclusion trails within quartz grain
Image Tags: none
Unique Identification: Quartz
Site name: not specified
Light type: Plane-Polarized Light
Magnification: not specified
Submitted by: not specified
Notes: Rutilated
Image Tags: none
Unique Identification: Quartz
Site name: not specified
Light type: Cross-Polarized Light
Magnification: not specified
Submitted by: Guy Rothwell
Notes: Field of poorly sorted angular quartz grains, anhedral
Image Tags: none