I can honestly say I’ve never really considered what glitter is and where it comes from, but this article from the New York Times is fascinating.
What is glitter?
What is glitter? The simplest answer is one that will leave you slightly unsatisfied, but at least with your confidence in comprehending basic physical properties intact. Glitter is made from glitter. Big glitter begets smaller glitter; smaller glitter gets everywhere, all glitter is impossible to remove; now never ask this question again.
There are a couple ways to achieve a rainbow effect on individual glitter particles, so useful for politics. Holographic glitter is made by embossing a fine pattern onto film, so that the surface reflects different colors of light in different directions — there is nothing intrinsically rainbow-colored about the glitter itself. Contrast this with more subtle iridescent glitter, which reveals various luminous colors depending on the angle at which it is viewed, and is made from a multilayered clear film, composed of polymers with different refractive indexes.
How many layers is multi?
“Two hundred and thirty three,” said Mr. Shetty, and grinned as he waved an almost invisible sheet of plastic. “It gets very technical,” he warned. “You know, the visible spectrum, and all.”
I nodded, indicating I followed.
“Each layer is half the wavelength of light,” he said.
“WHAT?” I wailed.