No, no, no, Bob was the closest with sugar.
They are, in fact, grains of table salt magnified 75 times.
Incidentally,the structure of mineral salt is as a cubic crystal. A single grain of Kosher salt is composed of many cubes, stuck together into a big grain. As a result, a single grain of Kosher salt can absorb much more liquid than a grain of granulated salt. Below is a photograph of a grain of Kosher salt, magnified 75 times.