GLENDALE COMMUNITY COLLEGE

EARTH SCIENCE IMAGE ARCHIVE

ASTRONOMY    GEOLOGY    METEOROLOGY    MUSEUM TOUR    PHS 120    PHS 120 ONLINE   HOME

Forms
Imperfections
Quartz Pictures
Varieties

 

BACK TO P,Q,R

Quartz comes in wide variety of forms, colors and varieties.  Follow these links to some useful information about the varieties of QUARTZ.

 
 

 

     Crystal lattice structure of Quartz.

 

  A common lump of Quartz showing conchoidal fracture and vitreous luster.

herk1.jpg (296078 bytes) A short prismatic crystal of Quartz in dolomite.  This is an example of a Herkimer Diamond from New York.

QTZXL1J.jpg (147187 bytes) Prismatic crystals of Quartz terminated with pyramids.

QTZXL2J.jpg (66967 bytes) A divergent cluster of Quartz prisms.

CHEMISTRY - SiO2  Silicon dioxide 

CRYSTALLOGRAPHY - Hexagonal - Trigonal trapezohedral

CRYSTAL GROWTH AND HABITS - Crystals can develop in a variety of ways.  Most commonly as hexagonal prisms terminated with pyramids.  It is also commonly microcrystalline as in chalcedony and chert.

COLOR AND OTHER OPTICAL PROPERTIES Quartz has a wide range of colors as it is easily tinted by minor amounts of impurities.  Colors include white, pink, yellow, brown, green, purple, gray and black.  It is transparent to nearly opaque.

HARDNESS - 7       SPECIFIC GRAVITY - 2.65        

LUSTER - vitreous        STREAK - white

BREAKABILITY Conchoidal fracture, brittle 

OCCURRENCE Quartz is very common is the felsic igneous rocks like granite and granitic pegmatites.  It is the dominant mineral in most sandstones and quartzites.