Brain sand is most commonly found in our pineal gland, but can also accumulate in other parts of the brain to a lesser extent.

According to Wikipedia, brain sand is made of various minerals include calcite, calcium phosphate, calcium carbonate, magnesium phosphate, and ammonium phosphate. Interestingly, as these rocks accumulate in our heads as we age such that by middle age they make our pineal glands show up clearly on some types of brain imaging.

Unlike otoliths, the functions if any of brain sand remain unknown. Darn. If I’m going to have rocks in my head I’d like to know what they are doing there.

Some folks think that crystals have magical powers so the notion that we have crystals in our brains might lead some to think they give us supernatural abilities. This idea is amplified by the thought by some that the pineal gland, home to brain sand, gives us psychic powers. Science and medicine tell us that the pineal gland regulates sleep and body rhythms in part via melatonin production.

It’s interesting to think about the fact that we have these rocks in our heads. I hope that someday we will know why the brain sand is there.