Purple

It took twelve thousand sea snails to dye the border of a single robe.

Tyrian purple was extracted from the gland of a sea snail, and it only turned purple once sunlight acted on the secretion. It cost more than its weight in gold. That's why wearing it head to toe, without the rank for it, could be read as treason.

Today purple is the cheapest color there is — a synthetic dye since 1856. No color has ever fallen so far.

color as a political instrument

The dye comes from the hypobranchial gland of sea snails of the genus Murex (Murex trunculus, Murex brandaris), native to the eastern Mediterranean coast — in what's now Lebanon — and produced mainly by the Phoenicians. It took on the order of ten to twelve thousand snails per gram of dye: twelve thousand specimens of Murex brandaris yielded barely 1.4 grams, just enough to dye the border of a single robe. The larger Murex lived in deep water and had to be dredged from around 25 fathoms down. The main compound is 6,6′-dibromoindigo, and different species produced different shades. Unlike almost every other ancient dye, it didn't fade in sunlight — which made it even more valuable. In Diocletian's Edict on Prices, it was priced above gold.

From costly luxury it became a regulated political instrument. Senators wore the latus clavus, a broad purple stripe on the toga whose width signaled rank. The toga picta, entirely purple and shot through with gold thread, belonged to the triumphant general. The darkest shade — nearly black in shadow, deep red in sunlight — was reserved for the emperor; wearing the fully purple toga without the rank for it could be treated as treason. Magistrates and freeborn children were only entitled to a narrow border, the toga praetexta. Production collapsed with the sack of Constantinople in 1204 — no later ruler could gather the resources it required — and the imperial workshops disappeared with the city's fall in 1453. The detail that changes everything for a designer: Tyrian purple wasn't lilac. It was a dark red-violet, wine- or blood-colored. The bright purple we picture today comes from synthetic mauve (mauveine), dating to 1856 — no emperor ever saw that color.

mourning and devotion

Many devout Catholics wear purple, alongside black, during mourning. A striking nuance: wearing purple without attending a funeral can be seen as disrespectful or bad luck, given its sacred and devotional weight. In the Good Friday procession, men and boys wear purple robes and hoods as a sign of mourning and a symbol of the suffering of the crucifixion.

mourning — reserved for widows

Purple is associated with grief and reserved for widows in mourning for a spouse; the rest of the funeral attendees wear black. It isn't simply "purple means mourning in Thailand" — the color marks a specific position within the mourning process, not a generic emotion.