"Crystalline" is a song by Icelandic artist Björk, released as the lead single from her eighth album Biophilia. The song was released as a single on June 28, 2011 accompanied by an iPad app developed exclusively for the song. It was afterward released as part of The Crystalline Series alongside the second single from the album, "Cosmogony".

Crystallinity refers to the degree of structural order in a solid. In a crystal, the atoms or molecules are arranged in a regular, periodic manner. The degree of crystallinity has a big influence on hardness, density, transparency and diffusion. In a gas, the relative positions of the atoms or molecules are completely random. Amorphous materials, such as liquids and glasses, represent an intermediate case, having order over short distances (a few atomic or molecular spacings) but not over longer distances.