May 15, 2001

What substance, worth its weight in gold (and then some), was the singular basis upon which were countless wars fought, economies catapulted and lives lost? No, the answer isn't cocaine, but an entirely different cash crop—murex purple. Used to dye the clothing of the royal and religious, murex purple has a special place in the history of dress.

Sources of Purple Dye

In order to understand why a particular color of clothing would have conveyed such prestige it is necessary to learn a little bit about the history of this particular dye. At one time, dyes, such as purple, scarlet, yellow and indigo were made from natural plant, animal and mineral products. The products were often dried, pulverized and then mixed with liquids in order to form dyes for clothing and other textiles. (Today, many dyes for clothing are made synthetically in laboratories, through chemical processes involving products such as aniline.)

The purple dye used in ancient religious and royal robes most likely came from one of several types of shellfish: a) Murex brandaris, b) Murex trunculus, c) Helix ianthina, d) Purpura lapillus, or perhaps e) Purpura haemastoma. One legend suggests that the dye was discovered by Helen of Troy, who when strolling along the beach to pass the time while in captivity, noticed that her dog had chewed into a large shellfish and its mouth had become purple as a result (Jensen 1963: 106).

The two chief sources for this purple dye are Murex trunculus and Murex brandaris, and the shades of dye produced these sources can range from bright red, to blue, and to deep, almost black, purple. The dye extracted from these shellfish is extremely valuable (hence the prestige associated with purple clothing), since it's not only rare but also costly to produce. Only a few drops of the liquid used to make the dye can be extracted from each shellfish, and, according to one recipe, in order to dye 1,000 pounds of wool, 111 pounds of the Murex secretion and 200 pounds of the Purpura secretion were required (Stieglitz 1994: 46). According to Renata Pompas, "it was necessary to have 12,000 murex or molluscs for 1.4 grams of pigment, scarcely enough for dying a single dress the size of the Roman toga." It is no wonder then, that this dye was used primarily to treat the garments of wealthy or privileged individuals.

As Pliny the Elder notes in his Natural History, the dye was created through a lengthy process of distillation:

There is a white vein with a very small amount of liquid in it; from it is obtained that well-known dye which shines faintly with a deep rosy colour, but the rest of the body is unproductive.

[...] Men try to catch the murex alive because it discharges its juice when it dies. They obtain the juice from the larger purple-fish by removing the shell; they crush the smaller ones together with their shell, which is the only way to make them yield their juice.

[...] The vein already mentioned in removed, and to this, salt has to be added in the proportion of about one pint for every 100 pounds. It should be left to dissolve for three days, since, the fresher the salt, the stronger it is. The mixture is then heated in a lead pot, with about seven gallons of water to every fifty pounds, and kept at a moderate temperature by a pipe connected to a furnace some distance away. This skims off the flesh which will have adhered to the veins, and after about nine days the cauldron is filtered and a washed fleece is dipped by way of a trial. Then the dyers heat the liquid until they feel confident of the result. A red colour is inferior to black (138).

Although this recipe is ancient, variations of it are still used today. Jensen states that he encountered some children on the Syrian coast who had mashed murex shells and the mixed the snail extract with lemon juice and then used the mixture to dye some rags (Jensen, 104).

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