Azurite

What color is azurite?

The story of azurite

Azurite is the blue that painted most of the skies in medieval Europe, and a good number of them have since turned green.

The stone is basic copper carbonate, the blue twin of green malachite, and the two grow together wherever copper ore weathers. Egyptians were using it by the Fourth Dynasty, around 2600 BC, and it turns up in Eighteenth Dynasty wall paintings. Because it came out of the ground rather than a workshop, and Europe had copper mines while Afghanistan was a long way off, azurite was the blue you could actually get.

From the Middle Ages into the 1600s it was the most common blue in European painting, more common than ultramarine, which got the glory. Ultramarine was ground lapis lazuli shipped from Afghanistan, at times valued as highly as gold, so it went on the Virgin's robe and almost nowhere else. Azurite went everywhere else: skies, portrait backgrounds, the layer beneath a thin ultramarine glaze to stretch the expensive stuff, and, mixed with yellow, the greens of foliage. Hungary supplied most of it until the Ottoman invasion in the mid 1600s, Saxony mined it from the 1100s, and the Italians called it azzurro della Magna, blue from Germany.

Two things about it every painter had to learn. First, grind it coarse: fine azurite goes pale, so workshops kept the grains big and the washes gritty. Second, it does not stay blue. In oil it drifts slightly green; over centuries, damp and air turn it toward malachite and green copper chlorides, and sulfur darkens it. That is why the Madonna's mantle in a Raphael altarpiece has a greenish cast, why the blues in Michelangelo's Entombment have gone olive, and why so many medieval skies are now the color of pond water. Cennini's test for telling it from ultramarine was fire: heat a pinch and azurite goes black.

China and Japan never had the same anxiety. From the 400s BC the official Chinese palette paired azurite blues with malachite greens, and the two minerals became the blue-and-green landscape, mountains laid in as flat opaque color to mean somewhere ancient or somewhere blessed. In Japan the ground stone is iwa-gunjo, graded by grain from coarse and dark to fine and pale, and gentle heating deepens the blue. Japanese painting still uses it.

Then a paint maker in Berlin ruined a batch of red. Around 1706 Johann Jacob Diesbach was making a cochineal red with potash contaminated with blood, and got a deep blue instead. Prussian blue was cheap, strong and did not turn green, and within a generation azurite lost its place as Europe's everyday blue. I like azurite more for its failures than its successes. Every green-skied altarpiece is a record of a painter who could not afford the good blue and used the honest one, and four hundred years later the chemistry told on him.

Pigment facts

These describe the pigment in general. Every brand's tube behaves a little differently, so test yours on scrap paper.

How to mix azurite

You can get the color in one step: a violet-blue and a green-blue, about equal, meet in the middle at azurite. What you cannot mix is the grain. The pairing that matters is blue and yellow, the historical one: azurite plus yellow ochre made the greens of Renaissance foliage, and Rubens built a green skirt in his Gerbier family portrait from azurite and yellows. Try it and you get a soft, believable leaf green in seconds.

To fake the mineral, drop the two blues into a wet wash separately; they settle at different rates and dry mottled, like ground stone.

Using azurite in watercolor

Use it where an old painting would have: a sky meant to feel medieval rather than Mediterranean, the plain blue ground behind a portrait, the shadowed folds of a robe. It is a working blue, not a showpiece, and that is its charm.

The technique that suits it is a two-blue wet-on-wet sky. Wet the paper, drop Twilight Indigo along the top and Glacier Blue lower down, tilt once and leave it. The two settle differently and dry with the grainy look of a real mineral wash.

It pairs with yellow ochre, a warm red and gold, the colors it spent five centuries beside in altarpieces.

One thing I learned the hard way: a blue that leans green makes a muddy purple. If you want violets, use the violet-blue alone. Keep this mix for skies and greens, and stop fiddling once it is down, because every stroke smooths out the grain you wanted.

Azurite vs ultramarine (and Prussian blue)

Ultramarine is the one it always gets compared to, because for four centuries they shared a palette. Ultramarine is ground lapis lazuli, violet-leaning, and it stays blue; priced at times like gold, it went on the Virgin and the Christ child. Azurite is greener, coarser, cheaper, and it slowly turns toward malachite. Painters often laid azurite underneath and finished with a skin of the good stuff.

Prussian blue is the one that ended it. An iron compound made by accident in Berlin around 1706, it is deep, strong, staining and stable, and it cost a fraction of either stone. Within a generation it was Europe's everyday blue and azurite was a curiosity.

If azurite is a medieval sky that has quietly gone green, ultramarine is the one robe in the picture that never changed, and Prussian blue is the factory that put them both out of work.

More color stories

Mel, founder of Tobio'sI make portable watercolor kits and I named the company after my cat. I write these pages for the beginner I used to be, one pigment at a time.