Quartz is a natural resource obtained through mining or imported from the World Map. As of v0.5.3, the only use of Quartz is to create Sand by two crushing cycles via the intermediate, Quartz Crushed. Note that the sand manufactured from Quartz is the same as natural sand which is more versatile (e.g., it can be used in silicon production) than the Manufactured Sand created from crushing Rock.
Below are all the recipes, which contain this item. Note, that some of them may be locked behind Research, and not immediately available in your game.