This rather pretty and slightly fractalicious image is a micrograph of some naphthalene crystals, taken in polarised light. Naphthalene is an aromatic hydrocarbon, with two rings fused together (not polycyclic, just bicyclic). Interestingly, the crystal in the image looks a little bit like a snowflake. This is probably because aromatic hydrocarbons like naphthalene are made up of hexagonal rings, the same way that the clusters of water molecules that make up snowflakes are also hexagonal.
Being a major component of coal tar, as well as one of the many compounds formed readily in soot and car exhausts, naphthalene is an abundant molecule. Which is also why it’s one of those elusive hydrocarbons which crazy scientists like myself try to prove the existence of in interstellar space. One instance has been reported of a detection of ionised naphthalene in an interstellar cloud… but that detection remains unconfirmed so far. It’s bound to exist there. It just needs to be proven to.
Frankly, interstellar space is probably the best place for naphthalene. It’s a particularly pungent smelling chemical, with an odour detectable down to 0.08 parts per million. And people still put this stuff in their wardrobes to keep moths away!