I have been listening to lectures on the history of ancient Egypt, a Teaching Company course presented by Professor Bob Brier. In the last of my 48 lectures on ancient Egypt, Dr. Brier mentioned an interesting detail about Cleopatras daughter by Marc Antony, Cleopatra Selene. Apparently, Cleopatra Selene married King Juba of Mauretania and had two children, a son and a daughter. Cleopatra and Juba had developed a thriving export business due to the high concentration of murex snails in the waters off the coast of Mauretania. Murex snails are the source of one of the best dyes in the ancient world. Anyway, Cleopatras son, Ptolemy, decided to travel to Rome to visit his cousin Caligula. Ptolemy wore a rich purple cloak dyed with his familys trademark product. When he got to Rome, Caligula was so upset that Ptolemys cloak was such a richer purple than his own that he had Ptolemy killed.
Murex was a highly valued source of dye in the ancient world. I found this excellent collection of papers about it.
"Although Pliny describes many varieties of purple, there were just two main categories, Hyacinth Purple and Tyrian Purple, that were produced from different species of shellfish: the former from banded dye-murex (Ph. trunculus) and the latter mainly from spiny dye-murex (B. brandaris)," writes Irving Zidernman. "The controversy as to whether banded dye-murex produces a unique violet (hyacinth) colour or the same purple hue as Tyrian purple has raged since the dye source was rediscovered in the 1830s."
Brendan Burke writes, "According to Julius Pollux (Onomasticon I, 45-49), writing in the second century AD, purple dye was first discovered by Herakles, or rather, by his dog, whose mouth was stained purple from chewing on snails along the Levantine coast, the area most famous in antiquity for its purple dye. Palaephatus (De Incred 62) also attributes the discovery of purple dye to Herakles and locates it at Tyre in the mid-second millennium B.C. King Phoenix received a purple-dyed robe from Herakles and decreed that the rulers of Phoenicia should wear this colour as a royal symbol.
Although the Levantine coast and the people of Tyre were renowned for their purple in antiquity, the earliest archaeological evidence for purple-dying from sea-snails in the Mediterranean is found on Crete. The earliest known deposits of murex shells on Crete, in quantities substantial enough and worn in such a way as to suggest dye-extraction, occur on the small island of Kouphonisi, at Palaikastro, and at Kommos. Pottery found at these sites suggests a date within the early Middle Minoan period, ca. 20th-18th c. B.C. Slightly later finds of murex shells occur elsewhere in the Aegean, at Troy, and in the Levant.
See also: http://www.convertingloop.com/cgi-bin/cl.pl/db_area/converting/paper_film_foil/2002/pffc20020701.1.shtml