We pride ourselves here in Ireland (and especially Wexford!) on our sandy beaches, but what is sand and why is sand so varied in both grain colour and size?
Next time you go to the beach grab a handful and examine. What colour? It’s going to be composed mainly of the our most abundant minerals silica (quartz) and feldspar which over millennia weathers away further inland and eventually makes its way to the coast by river. As a result of all this quartz we have a beige/pale-brown coloured sand. The little silvery sparkle you see in the sunlight is due to the same shiny stuff you see in granite (mica, only about 1%!) The presence of other dominant rock and shell can also give various hues to the sand. Have a look at the cliffs/top shore-Is it red sandstone? black limestone? Can you make the colour out in the grains? What size? Typically the finer the grains, the older the beach as wave power and time have worn the grains right down. Beaches with larger grains and gravel/pebbles are considered younger, although if there are strong currents and waves associated here, all the finer grains are taken away and only larger sediment remains!?
Google ‘most colourful beaches in the world’ just to see the diversity worldwide from the green Olivine Papakolea beach in Hawaii to the purple Pfeiffer beach in California. Below is a pic from Dollar Bay. The sediment from the headland mixes with the sand as it flows down to the tide.
Natures art at her best.