A Journey with Lapis Lazuli Pigment

Just look at that – a beautiful precious Blue, its subtle variety of shades and striations, shot through with streaks of calcite and glittering iron pyrites, describing some imaginary landscape. It is the original royal-blue, the best blue ever, valued as a jewel and a pigment for millennia  both in  the Occident and the Orient. It graces the pages of the most opulent and sumptuous manuscripts of the Medieval and Renaissance periods, along with gold, cinnabar, red lead and copper greens, equally valued as the ornaments of choice for volumes sacred and secular in Christendom and the Islamic world.

The first time I encountered a quantity of fine quality lapis pigment was in the very early 1990s, when I met David Margulies, who had a shop in Hampstead selling specialist materials for artists. The name of this shop – “Lapis” – hinted at David’s primary sphere of interest, and when I expressed my interest in buying some real lapis lazuli pigment, I was invited to the lower floor where he kept his precious samples. He was more than happy to talk about his work, about the history and the characteristics of the mineral, and the many experiments he had undertaken in his quest for the best way to produce the perfect pigment. Boxes full of vials containing different qualities that he had prepared, a range of magnificent  samples showing the mineral in its different habits, and nineteenth-century mahogany paint boxes containing  real ultramarine watercolours prepared by Messrs. Winsor & Newton or Reeves were ranged before me. I was mesmerised by the stories that unfolded as he talked about his treasures.

I took a small vial of David’s finest, and started to experiment in earnest with the painting qualities of real ultramarine, contacting David from time to time to relate my experiences with the colour. A friendship has grown over many years of sharing our research and discussing the outcomes, often centred around this one pigment, and I think it is time to share something of what we have gleaned from this fruitful enquiry.

David Margulies uses Lapis Lazuli that has been mined at Sar-e Sang in the mountainous Badakhshan province of what is now Afghanistan. These legendary mines have been worked  continuously since ancient antiquity, and continue to produce an abundance of the mineral, the seams of blue running through massive matrices of brittle white calcite. The rich blue material is Lazurite (not to be confused with Azurite, which is copper carbonate). It is a complex compound that contains sulphur, and the rock varies in quality depending on the ratio of lazurite to calcite. There is also a rare occurrence of almost pure lazurite crystals or nodules completely encased in calcite. These nodules are relatively brittle, unlike the phenomenally hard lapis lazuli rock, and are therefore unsuitable for making jewellery or for carving objects, so they have been overlooked for a long time. It is this, as David demonstrates, that produces some of the best pigment.

Like many historical processes associated with the production of pigments, the making of lapis lazuli pigment has been routinely obfuscated by a culture of secrecy, mystique, and half-understood process. The worst offender, to my mind, is the recipe quoted in Daniel V. Thompson’s 1933 translation of the 15th century Italian treatise “Il Libro dell’Arte” by Cennino d’Andrea Cennini”, a generally fascinating account easily available from Dover Publications inc. (everyone should have a copy). Outdated popular scholarship based on a transcription of an obscure craftsman’s account is fascinating, but is better enjoyed for what it is rather than regarded as the ultimate authority, as sadly many researchers have been content to do.

Of course, we had to try, as part of our journey, the preposterous recipe under “On the character of ultramarine blue, and how to make it” that begins on page 36 and continues for three more pages. It involves mixing up finely ground lapis lazuli with mastic, linseed oil and wax to make a ‘plastic’ which is then laboriously kneaded over days and weeks in a bath of lye in order to leech off the pure lazurite particles, leaving behind the adulterating calcite and pyrites that are so difficult to separate. A perfect way to waste weeks of your time and a quantity of expensive mineral, for the yield is pitifully minute, and the ‘plastic’ soon hardens into an unworkable lump, trapping most of the lapis within.

Lapis lazuli pigment was ruinously expensive in the West; it was also a pigment for the elite in the Islamic Middle East. Like gold, it was used extensively in workshops patronized by the nobility and royalty. Therefore efficient techniques were required, by specialist colourmen, to produce adequate quantities of top quality pigment for the use of the master painters and illuminators of the ateliers. The crystalline, lazurite-rich nodules have minimal unwanted inclusions and cost less labour to pulverize, so there is no reason to suppose that they were not used in the Middle East where the mines were in closer proximity. There is also a hint in a 17th century Persian treatise by Qadi Ahmad (sic) son of Mir Munshi translated in 1959 by V. Minorski (Freer Occasional Papers) of the employment of a simple form of froth-floatation to separate out the pure lazurite. After the mineral is pounded and sieved, it is “washed with Iraqi soap” :

” One pours some water into a vessel and beats up the said soap into a foam, so that the lye becomes sharp. The sifted stone is cast into the water, stirred up and left for an hour until the agitated water becomes calm. Then that water is poured into a different bowl and the hard residue is collected, pounded again, washed with lye, and put in another vessel….”

Repeating the process with the residue produces different grades of colour, starting with the richest, gradually becoming paler as the ratio of lazurite to calcite reduces. The heavy pyrites are completely discarded.

Powdered lapis lazuli pigment is cornflower blue when dry – with the addition of a medium such as gum Arabic, its colour deepens to the richness of the best stones. I found that the particles needed to be ground more finely with a glass muller, but be wary of the tell-tale odour of sulphur, which means that the lazurite is breaking down and losing its colour. Further filtering refines the colour even more, and of course, one must always recycle by using a clean vessel of distilled water for painting, and saving the residue that collects in the water from the brush while working. The colour does not handle at all like modern watercolour paints. It is dense, heavy, and completely opaque, requiring a particular approach to its application. I have covered some of these properties in a number of academic presentations, one of which: “A visual analysis of the illuminated opening pages of a sixteenth-century Iranian manuscript…..” I have posted at academia.edu