In order to procure the animal, the shell must be broken with a sharp blow of a small hammer, and the receptacle of the colouring matter can then be seen behind the head, and recognised by its lighter hue.
When it is opened, a creamy sort of matter exudes. It is yellowish, and gives no promise of its future richness of hue. There is only one drop of this matter in each animal, and it is about sufficient in quantity to stain a piece of linen the size of a dime.
The best mode of seeing the full beauty of the purple is to take a number of the Molluscs, and to stain as large a surface as possible. The piece of linen should then be exposed to the rays of the sun, when it will go through a most curious series of colours. The yellow begins to turn green, and, after a while, the stained portions of the linen will be entirely green, the yellow having been vanquished by the blue. By degrees the blue predominates more and more over the yellow, until the linen is no more green, but blue. Then, just as the yellow yielded to the blue, the blue yields to red, and becomes first violet, then purple, and lastly assumes the blood-red hue of royalty.
The colour is very permanent, and, instead of fading by time, seems rather to brighten.
In some cases the ancients appear not to have troubled themselves with the complicated operation of taking the animal out of the shell, opening the receptacle, and squeezing the contents on the fabric to be dyed, but simply crushed the whole of the Mollusc, so as to set the colouring matter free, and steeped the cloth in the pulp. Tyre was one of the most celebrated spots for this manufacture, the "Tyrian dye" being celebrated for its richness. Heaps of broken shells remain to the present day as memorials of the long-perished manufacture.
The value which the ancients set upon this dye is shown by many passages in various books. Among others we may refer to Herodotus.
Cambyses, it appears, had a design to make war upon three nations, the Ammonians, the Carthaginians, and the Ethiopians. He determined to invade the first by land, and the second by sea; but, being ignorant of the best method of reaching the Ethiopians, he dispatched messengers to them, nominally as ambassadors, but practically as spies. He sent to the King of Ethiopia valuable presents—namely, a purple mantle, a golden necklace and bracelet, an elaborate box of perfumed ointment, and a cask of palm-wine, these evidently being considered a proof of imperial magnificence.
The Ethiopian king ridiculed the jewels, praised the wine, and asked curiously concerning the dye with which the purple mantle was stained. On being told the mode of preparation, he refused to believe the visitors, and, referring to the changing hues of the mantle and to the perfume of the ointment, he showed his appreciation of their real character by saying that the goods were deceptive, and so were the bearers.
The Hebrew word argaman, which signifies the regal purple, occurs several times in Scripture, and takes a slightly different form according to the Chaldaic or Hebraic idiom.