What Type of Rock is Quartzite?

Quartzite Tough Metamorphic Rock

Quartzite is composed almost entirely of quartz formed through the metamorphism of sandstone.  Sandstone is a common sedimentary rock.

Sedimentary rocks are composed of minute grains of quartz.

Quartzite is a rock not a mineral.  Whilst most rocks are made up of several minerals some are made up of just one. 

In its purest form quartzite is mostly white or grey.  Inclusions of other minerals bring about a change in colour.  Iron oxides introduce shades of red, pink or brown.  Chromium rich mica turns quartzite green.

Green quartzite is better known as green aventurine.  Aventurine can occur in several different colours although green is the most common.  
 
Quartzite is an extremely hard stone that's resistant to chemical weathering.  It can sometimes resemble marble which formed through the metamorphism of limestone. 

Marble is softer than quartzite.

The reason quartzite is so tough and durable is because of its tightly interlocking grains of quartz.

Article Picture

The quartzite photo in our article is clickable and redirects to the original image. Courtesy of Stan Celestian