Magnetite: The Dark Side of our Sand

Before he became Dark Vader, Anakin Skywalker once said “I don’t like sand. It’s coarse and rough and irritating and it gets everywhere.” What Anakin failed to recognize is that sand actually has a dark side to it. Well, our sand does, at least (I can’t speak for the desert planet of Tatooine). What I am talking about is Magnetite; that dark stuff that appears on our beach every once in a while:

MAGNETITEMagnetite is one of many minerals in our sand. Its dark color and heavier weight is what makes it stand out on windy days, while quartz and lighter sediments blow around. Also, magnetite is magnetic! So bring a magnet with you the next time you’re on the beach and have a blast!

Too bad Anakin didn’t know about this dark side of sand. His path would have been much shorter, sparing us of those terrible prequels.

For those who are actually really interested in this topic and the sedimentology of our beaches, please visit

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3 thoughts on “Magnetite: The Dark Side of our Sand”

  1. I always thought that some of that discoloration was dirt and debris that got mixed in when they picked up all the sand after Sandy, trucked it down to the Superblock, then sifted and trucked it back?

  2. Most “dirt” and debris get quickly washed from the sand. Even oil, which causes discoloration is an organic mineral that breaks down rather quickly. Same with sewerage.

    For a century, New York City dumped sewerage solids and raw garbage three miles off our coast. The vast majority of it disappeared like magic — quickly broken down by the ocean.

    On occasion, you’ll see an oil stain at the shoreline, but usually black streaks on a sandy beach is a mineral like granite, or if it’s magnetic, magnetite.

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