Gary has sent in a couple of links that people may find stimulating – Sahara sand under the microscope. See http://vixra.org/pdf/1102.0022v1.pdf and www.myspace.com/jonlarsenguitar/photos/51836900
The mystery is there are micrometeorites in sand – in desert soils, in beach sand, and in glaciers. The deposition of micrometeorites can be found vritually anywhere – even in downpipes from the gutter of your house. Iron micrometeorites can be found with a magnet.