Murex is a genus of medium to large sized predatory tropical sea snails. These are carnivorous marine gastropod molluscs in the family Muricidae, the murexes or rock snails.
The common name "murex" is also used for a large number of species in the family Muricidae, most of which in the past were originally given the Latin generic name Murex, but most of which have now been grouped in other newer genera.
The word murex was used by Aristotle in reference to these kinds of snails, thus Murex is arguably one of the oldest classical shell names still in use by the scientific community.
This dye was used in royal robes, other kinds of special ceremonial or ritual garments, or garments indicating high rank. It featured prominently in the ancient Temple in Jerusalem, the clothing of the High Priest (or Kohen Gadol) officiating there and continues to be used today by Jews who wear the ritual garment known as a Talit.