Being the inquisitive type I borrowed my son's microscope to look at the sand caught in the filter on my well water line (from about 60' down) which was dug some fifty years ago. Interesting things here. About half of the sand was magnetic and would tightly stick to a magnet. Occasional grains were perfectly round, while others looked like twisted quartz, some being clear as glass. Still others were a translucent red. The ones photographed puzzle me, they look like tiny doughnuts which vary in color from white to gray, and in diameter with some being only half the size of the ones shown. The scale is graduated .01". I think they are much too small to be part of a crinoid, and nothing else there resembled a fossil. Anyone know?