Marble is a mineral that is made up of calcite (calcium carbonate, CaCo3). Chemical impurities add to this formula, as do physical inclusions.

Quartzite is an abundant metamorphic rock. It occurs naturally when sandstone or chert rich in quartz experiences heat and high pressure. Quartzite is typically made of more than 90% quartzite; some can get as high as 99%. Quartzite has a glassy appearance and resembles marble in some cases.

 
Similarities

Marble and quartzite look very similar and might be hard to tell apart. They both appear to be very elegant and stylish. The colors may at times appear to be very close and even the visual texture of these two stone looks similar. Both stones have a crystalline appearance when viewed closely. This is because the minerals that make up these rocks are actually crystallized. As the images below show, these stones can be very tough to tell apart. For this reason, it is a good idea to know how to tell the difference.

In addition to visual appearance, they are both of the metamorphic rock type. Metamorphic rock is rock that started out as a different kind of rock before its metamorphosis.

 
Differences

One of the biggest differences between these two natural stones is their hardness. Quartzite is harder than any marble. On the Mohs hardness scale, quartzite rates a 7; marble, around 3. The reason for the difference in hardness is the minerals that each stone is composed of.

Softer stone is more workable for some application that harder material. Furthermore, hard material can be more brittle and might require caution when cutting, drilling, or grinding the surface. Marble has been used for millennia for building construction, sculpture, flooring, and other purposes. Marble is a well-known material for use by sculptors. One reason is because of how easily it is shaped and smoothed.

The reason for these differences between marble and quartzite is mainly because they contain different material. Quartzite is made of primarily quartz whereas marble is composed of calcite. In fact, the calcite is what makes marble so easy to work and the quartz is what makes the quartzite so hard.