Hexaplex trunculus (previously known as Murex trunculus, Phyllonotus trunculus, or the banded dye-murex) is a medium-sized sea snail, a marine gastropod mollusk in the family Muricidae, the murex shells or rock snails. It is included in the subgenus Trunculariopsis.
This species is a group of opportunist predatory snails that are known to attack their prey in groups. Unlike other sea snails, they show no preference for the size of their prey, regardless of their hunger levels.
Tekhelet (Hebrew: תְּכֵלֶת təḵēleṯ) is a blue dye that historically held great significance in ancient Mediterranean civilizations. It is mentioned in the Hebrew Bible and is accordingly commonplace in Jewish culture, wherein it features prominently to color the fringes (called tzitzit) of several Jewish religious garments, such as the tallit. The dye was similarly used in the clothing of the High Priest of Israel and in tapestries in the Tabernacle.
Biblical texts do not specify the source or production method of tekhelet. Rabbinic literature, however, records that it was produced from a marine animal: ḥillāzon (חלזון). The practical knowledge of tekhelet production was lost over time, resulting in the omission of the dye from tzitzit. The ḥillāzon has been identified in contemporary times as Hexaplex trunculus.
Tyrian purple (Ancient Greek: πορφύρα porphúra; Latin: purpura), also known as royal purple, imperial purple, imperial dye, or simply tyrian, is a reddish-purple natural dye. The name Tyrian refers to the city of Tyre in ancient Phoenicia (modern-day Lebanon). It is secreted by several species of predatory sea snails in the family Muricidae, rock snails originally known by the name Murex (Bolinus brandaris, Hexaplex trunculus and Stramonita haemastoma). In ancient times, extracting this dye involved tens of thousands of snails and substantial labour, and as a result, the dye was highly valued. The coloured compound is 6,6'-dibromoindigo.