Quartz sand

Quartz is most important as a sand forming mineral, and present in very many sand types but usually not exclusively. In this sand type, quartz is almost the sole component of sand. Similar sandstones are called quartz arenites or orthoquartzites.

Quartz is most resistant to chemical weathering among common minerals. It is also relatively hard and therefore resistant to physical weathering as well. This means that sands get more and more enriched in quartz as time goes by and sands composed almost solely of quartz are mature and often have travelled far from the source area, sometimes thousands of kilometers.

Needless to say the mineral particles that make up this kind of sand can be very old. They may have broken away from their source rocks millions or even hundreds of millions of years ago and have perhaps seen several lithification and weathering cycles.

Good examples of sands enriched in quartz can be found in Florida. Sand from Siesta Key beach is sometimes called the whitest in the world, although it has competitors. Quartz rich sands are found on the coasts of passive continental margins (the edge of a continent without active volcanism).