Historical Pigments: Azurite

Like malachite, azurite has been in use since at least the third millenium BC. It reigned supreme as the most beautiful, celestial blue for a long time before lapis lazuli became widespread in Europe in the 14th century. It then remained an indispensable pigment, either in its own right, or to build up layers of blue to be finished with a glaze of lapis, the latter being both transparent and incredibly expensive.

Other names for the pigment: Copper blue, blue malachite, chessylite, mineral blue, mountain blue, blue bice, citramarine, azure of Almayne (“German azure”); Germany: bergblau (“mountain blue”); France: Bleu de la Magne, bleu d’Allemagne, azur d’Allemagne, bleu allemand (all meaning “German blue”), ocre bleue (“blue ochre”), cendre bleue (“blue ashes”); classically: lapis armenia; China: k’sing (“kingfisher blue”).

What it is: A basic copper carbonate, chemical formula Cu3(CO3)2(OH)2. Found in copper deposits.

Granulation: Yes. The pigment can be further mulled for a smoother paint film but the colour will get paler.

Compatible with: Egg tempera, egg glair, gum arabic, casein. Oil is too yellow and will make it greenish. Hygroscopic binders such as rabbit skin glue can be used but will offer no protection against humidity (see notes).

How to use it: 

  1. Place the needed amount in a cup and add a few drops of water, just enough to wet the pigment into a stiff paste.
  2. Add equal amount of gum arabic solution, or egg tempera, or glair, or casein, and mix well. (Note that gum arabic can be left to dry and then re-wet later. The other mediums are no longer usable once dry.)
  3. If using it coarse, ensure the binder is strong so that the relatively large particles adhere strongly to the support.

Notes:

  • Azurite has the peculiarity of turning back into malachite when exposed to humidity, meaning that in a damp environment, it will turn green over time. This happens because weathering replaces some of its CO2 units with water. This will take some decades in open air, but this is one pigment best not stored wet.
  • To the trained eye, azurite always tends to green and lapis lazuli has no such shade. In this way they can be told apart in old manuscripts, even when the scribe didn’t differentiate them. This was the norm in pre-modern Arabic, which only had one word for both minerals (Persian لازورد), thus giving the misleading impression that lapis lazuli was always used.
  • An azurite-painted surface will glitter with the mineral’s natural crystals, as shown in this video:

 

Several grades of my hand-ground azurite are available in the shop, while stocks last. See the sampler below for exact hues and granulation.


 

Extraction journal:

First the rock is ground into fine sand.

It is then transferred to a ceramic mortar for washing.

The first couple of washes yield large amounts of dirt.

The pourings then get increasingly blue.

The finest grade of all emerges at the very end.

I’m very fastidious when washing azurite, which results in a number of different grades. Some of the lower grades (such as Ashes in my sampler) still contain dirt as well as some malachite, making for incredibly interesting, moody, layered pigments in olive greens and desaturated teals.