Pigment

The first black was not mined or traded; it was raked out of the fire. Bones charred in sealed pots give a black that is deeper and warmer than soot, mostly calcium phosphate around a core of carbon. Cave painters drew aurochs with it. Rembrandt built shadow from it. Velázquez dressed his court in it. It has never been improved, only renamed.

Ivory black, its finer cousin, was once made from true elephant ivory.

Lapis lazuli left the mines of Sar-e-Sang by caravan and reached Venice by sea, which is how the blue got its name: ultramarine, from beyond the sea. Grinding the stone gives grey; the colour had to be kneaded out of it with wax and lye. Priced above gold, it was rationed by contract, reserved for the robes of the Virgin, and painters left works unfinished waiting for it.

Michelangelo's Entombment is said to have waited, unfinished, for a blue that never came.

The leaves are green, the vat is yellow, and cloth comes out of it the colour of straw. Then oxygen finds the dye and it blooms into blue within a minute. Indigo crossed every ocean, funded plantations and then broke them: in 1897 BASF began selling a synthetic molecule, identical atom for atom, and within a decade the plantations of Bengal had lost their market.

Your denim carries the same molecule, built in a reactor instead of a vat.

Verdigris is corrosion, cultivated. The Greeks suspended copper plates above wine dregs and scraped off the green crust; the women of Montpellier buried plates with grape skins and sold the harvest to painters. For centuries it was the most brilliant green on any palette, and the least loyal: it can shift, darken, even eat through parchment. Painters glazed it thinly and hoped.

The name is vert de Grèce, the green of Greece; the sickness was the product.

The pigment arrived in Europe as hard, foul-smelling balls called purree, and glowed like late afternoon. Where it came from was answered exactly once: an 1883 report from Monghyr, Bihar, describing cattle fed on mango leaves and little else, their urine boiled down and dried into cake. No second witness ever confirmed it. The trade vanished by 1908, one part chemistry, one part rumour.

Genuine Indian yellow fluoresces under ultraviolet light; the fakes do not.

Natural vermilion is ground cinnabar, hauled out of Almadén by convicts who rarely outlived the ore. The synthetic kind was the pride of alchemy: mercury and sulfur heated until a black mass sublimes scarlet. Rome loved it enough to cap its price by law. It still burns on the walls of Pompeii and in Chinese lacquer, and it keeps one flaw: given time and light, it can blacken.

The alchemists called it dry compounding: quicksilver and brimstone, sublimed to scarlet.

The glands of murex snails, salted and steeped, yield a liquor that dyes cloth a purple which never fades; sun and weather deepen it instead. Tyre smelled so strongly of the vats that the city was famous for both. Diocletian's price edict listed purple silk above gold, and later emperors reserved the colour outright: to dress in it uninvited was treason.

The only dye in this history that improves with weathering; everything else fades.