I was very intrigued by sand during the summer of 2018. Here are a few of the photos from my experimentation with a macro lens on the shore of Norton Gulch, Cape Arago. Some pieces of shells big enough you could still tell what they used to be: a fully intact shell, Sea Urchin spine, seaglass and gem stones. 
Sand is ubiquitous and grains of sand exist in numbers almost impossible to grasp. According to a study from the University of Hawaii, there are (approximately) seven quintrillion five quadrillion grains of sand on all the beaches in the world (7,500,000,000,000,000,000). Full write up can be found here.