This is not like crystalline ice, where it's a very compact ordered structure.

这种水冰不像结晶冰——结晶冰的结构非常紧凑有序。

The ordered structures that cause iridescence in opals are called photonic crystals, a kind of crystal where the bending and reflecting of light is happening in three dimensions in a periodic or repeated pattern.

在蛋白石中产生彩虹色的有序结构被称为光子晶体，一种以周期性或重复模式在三维空间内弯曲和反射光的晶体。