When quartz sandstone recrystallizes, it forms a metamorphic rock called quartzite.

Here's the process:

* Quartz sandstone: This is a sedimentary rock composed primarily of quartz grains.

* Recrystallization: Under heat and pressure, the quartz grains within the sandstone will dissolve and re-precipitate, forming larger, interlocking quartz crystals.

* Quartzite: This metamorphic rock is very hard, durable, and often has a sugary texture due to the tightly intergrown quartz crystals.