Quartz sand

Photo by John R Hobson

Westray beach sand composition

Shell sand. Photo by John R Hobson                               

A collection of sand samples from each beach revealed an interesting result as one or two beaches were 100% shelly sand and one or two were 100% quartz sand and others came in between with 80/20, 60/40 or 50/50. The graph shows a symmetrical curve from one extreme to the other. A couple of samples were taken from each beach, from somewhere in the middle of the beach and between the tide marks. They were then dried and microscope slides were prepared. Then, using a low powered microscope, a visual estimate was made of the percentage of each sand type. The estimates were made by more than one person and then averaged to obtain a reasonable though rough and ready result.