What is Quartzite?
Quartzite: A Tough Metamorphic Rock
Quartzite is composed almost entirely of quartz formed through the metamorphism of sandstone.
Sandstone, a common sedimentary rock, is composed of minute grains of quartz.
Quartzite is a rock, not a mineral, because it forms through geological processes that fuse grains of quartz into a solid mass. Although most rocks are composed of several minerals, some, like quartzite, are composed of just one - quartz.
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, while chromium-rich mica turns quartzite green.
Green quartzite is often known as green aventurine, but not all green aventurine is quartzite.
Quartzite is extremely tough and resistant to chemical weathering. It can sometimes resemble marble, which formed through the metamorphism of limestone. However, marble is softer than quartzite.
The reason quartzite is so tough and durable is because of its tightly interlocking grains of quartz.
Article Picture
Courtesy of Stan Celestian
