Excerpts from Jim Conrad's
Naturalist Newsletter

shell sand from the beach of the Yucatan, Mexico

from the June 26, 2011 Newsletter issued from Mayan Beach Garden Inn 20 kms north of Mahahual; Caribbean coastal beach and mangroves, ~N18.89°, ~W87.64°, Quintana Roo state, MÉXICO
SHELL SAND
If you sprinkle sand from our beach into the palm of your hand for a close examination, it looks like what's shown above.

The neat thing about our sand is that it's nearly entirely composed of tiny particles of coral and shells. In the above sprinkling I don't see a single piece I'd call quartz, which would dominate in a sand sample taken, say, from the bottom of a bayou back in Mississippi. In Mississippi sand we'd find irregularly spherical quartz particles and at least some tiny, black sheets of biotite mica, reddish hematite, pink or amber feldspar, and more.

In fact, sand is fascinating if you look at it closely. Once I backpacked from one side of Chihuahua's Copper Canyon to the other, and the only thing I brought back from the trip was a vial of sand collected in the bottom. I'd read that the canyon cuts through mineralogically interesting strata, so its sand should have been extraordinary, and it was.

I'm looking forward to making such pictures of sand in other places, so we can just sit back and admire more variations on the sand theme.