Soap bubble-like rainbow colors means that this sample has a thin film of
something on it, just like a soap bubble or oily puddle. The colors change
quickly, so there’s probably a ton of variation in the thickness of the coating
- in fact, the rainbow stripes are packed
![(Untitled)](/content/images/size/w795/ca622196c2f51e4a3f63493a6602b9bc/tumblr_mr9vcap1Rj1spzrmao1_1280.jpg)