azulène

CONT: L'azulène est un solide bleu (d'où son nom) fondant à 99 °C. [...] Certains dérivés de l'azulène existent à l'état naturel et colorent certaines sécrétions végétales.

OBS: azulene: [This] term is used to cover not only the parent hydrocarbon but the class of derivatives with the same basic structure, viz. [namely] a five-ring joined to a seven-ring, isomeric with naphthalene, which has two six-rings joined together.
OBS: Small quantities are added to shampoos and other products to impart the characteristic odor of chamomile. Also used as a coloring agent. Reportedly an anti-inflammatory agent. Nontoxic.