Earth Pigments – minerals

Although our research has not revealed a precise chronology for when particular earth colours were first discovered or the order in which they were used, scholars agree that their use dates back many thousands — in fact, hundreds of thousands — of years¹.

It is evident that haematite (natural red iron oxide) was used by Neanderthals approximately 200,000–250,000 years ago, while manganese and iron oxides (umbers and red ochres) are well documented as having been used by late Neanderthals approximately 60,000–90,000 years ago².

Whatever the exact dates, we can agree that the Earth has provided humanity with its most ancient palette.

The principal colourants are goethite (or, more broadly, limonite) and haematite, producing yellow-to-brownish and red colours respectively. Depending on which mineral predominates, the resulting natural iron oxide assumes its characteristic colour³.

Natural Yellow ochres

As with all earth pigments, yellow ochres are earths or clays coloured principally by iron oxides and therefore vary considerably in colour according to their geographical origin⁴.

The characteristic yellow colour comes primarily from the presence of goethite.

The English word ochre derives from the ancient Greek ὤχρα (ōchra), meaning exactly “yellow”.

Natural Yellow Ochre (Italy) — Limonite

Limonite was named in 1813 by the German mineralogist Johann Friedrich Ludwig Hausmann (1782-1859), from the Greek word λειμών (leimṓn), meaning “meadow”, referring to its common occurrence in wetlands⁵.

Today, limonite is generally understood as a generic term for naturally occurring hydrous iron oxides. Its characteristics fall within the range of those associated with goethite⁶.

Its colour ranges from light yellow to brown.

The particular Italian ochre used here is a bright, lemon-yellowish yellow.

Natural Yellow Ochre (France) — Goethite

Goethite is the principal colourant responsible for the yellow colour of ochres.

It was named after the German poet, novelist, playwright, philosopher, politician and geoscientist Johann Wolfgang von Goethe (1749-1832) in 1806 by the German mineralogist Johann Georg Lenz (1748-1832)⁷. French yellow ochre has long been considered one of the finest varieties in the world⁸, with a beautiful yellow colour.

We have the Foncé type.

Natural Red ochres

There are two principal types of natural red ochre: those produced by calcining yellow ochres, whereby goethite is transformed into haematite and consequently develops a red colour, and those in which haematite is already the predominant colourant, giving the earth its characteristic red colour⁹.

Haematite, or hematite, is a name attributed to the ancient Greek philosopher and naturalist Theophrastus of Eresos (370-287 B.C.), pupil and successor of Aristotle:

“πυκνὴ δὲ καì αἱματῖτις· αὕτη δ’ αὐχμώδης καì κατὰ τοὕνομα ὡς αἵματος ξηροῦ πεπηγóτος”¹⁰ (“and the haematitis is a compact material with a rough appearance; and as its name suggests, seems to be made of dried coagulated blood” ¹¹).

Indeed, haematite is not literally as red as fresh blood, but resembles the colour of dried blood.

Natural Red Ochre (France) – calcined goethite

This pigment is the result of calcining natural yellow ochre — in our case, the Foncé type. The process was patented by Atkinson in 1794¹².

The calcination of yellow ochre to produce red pigment had, however, been practised since antiquity, at least in ancient Egypt¹³ and Greece. A pigment-production site existed on the island of Kos, Greece, where earth pigments were processed, including through the calcination of yellow ochre¹⁴. Theophrastus describes this process in detail¹⁵.

Humanity had therefore been familiar with the transformation of yellow earth into red pigment since the Palaeolithic period¹⁶.

Natural Persian red

Gelak soil, as it is locally called¹⁷, is a highly distinctive red earth found in present-day Iran, formerly Persia, particularly on Hormuz Island in the Persian Gulf. The island is renowned for its exceptionally high-quality red ochre, distinguished by its unusually high concentration of haematite¹⁸.

It has been valued as a special red pigment since at least 2290 B.C. There are records of red ochre being traded from Magan (the region corresponding approximately to present-day Oman and the UAE) to Ur in present-day Iraq, alongside ivory, copper, bamboo and precious stones¹⁹.

Modern exploitation began privately in the early 20th century, before being taken over by the Iranian government in 1935²⁰.

The pigment used in our colours comes from the same source. As long as the ore body remains available, we will continue to use it; unfortunately, its remaining availability is not expected to last much longer, hence the limited production.

Natural Caput Mortuum

Caput mortuum, meaning “dead head” or “skull”, is an intriguing name that naturally evokes something dark.

In fact, caput mortuum was an alchemical term for the useless residue left after distillation²¹. It was symbolised by a skull, representing its perceived uselessness and its final, “dead” state.

It has often been — and still is — confused with Mummy Brown²², a brown pigment historically made by grinding actual ancient Egyptian mummies²³, in other words, human remains. The confusion probably arises from the similarly morbid names and the dark, brownish colour. Caput mortuum is also frequently, and incorrectly, considered to be simply another form of ochre²⁴.

True caput mortuum must consist predominantly of haematite. Although natural red ochres can be produced by transforming goethite into haematite through the calcination of yellow ochres, caput mortuum cannot simply be produced by calcining goethite²⁵. The haematite must already be present at a high degree of purity.

In our oil colours, the mineral haematite contains more than 85% iron oxides, exceeding the 80% level required for this classification.

Its precise colour also depends on the grain size, and we have selected the most neutral variety. Haematite has been used in art alongside natural ochres since prehistoric times, producing colours ranging from red to purplish-brown²⁶.

In our research, we found no definitive scientific evidence explaining why haematite became associated with the alchemical term caput mortuum as a pigment. We can only speculate that an alchemist may have encountered a residue whose colour resembled dried blood — just as haematite itself does.

Green earths

Iron is once again responsible for the characteristic colour of these earth pigments. Celadonite and glauconite, both iron-containing minerals, are the principal sources of naturally occurring green earths²⁷.

Celadonite forms in vesicular cavities and fractures within volcanic rocks, whereas glauconite occurs mainly in marine sedimentary deposits²⁸. The two minerals consequently produce different shades of green²⁹.

Green earths have been known and used since antiquity³⁰.

It is common for pigments to be sold simply as “green earth” without actually being composed of green-earth minerals. In some cases, the name refers only to the colour, with the pigment being blended with phthalocyanine green (PG7)³¹, probably to enhance its greenness and tinting strength. Genuine green earths are transparent and have relatively subtle chromatic strength.

Terre verde (Nicosia) – celadonite

Nicosia in Cyprus is known for its beautiful celadonite green earth, characterised by a unique, fine blue-green tint and remarkable quality. It was most probably used from very early times³².

It has been identified in figurines from ancient Cyprus (750–475B.C.)³³ and in frescoes in Italy, including examples from Ancona and Pesaro-Urbino³⁴. Cyprus, however, has remained famous throughout history as a source of this exceptional natural green pigment³⁵.

The same exceptional pigment is used in our oil colours.

The name of the mineral, celadonite, originates from the ancient Greek word Κελαδών (Celadon), which derives from κέλαδος (kelados), referring to a rushing or roaring sound, such as the sound of rushing water. Κελαδών first appears in Homer’s Iliad as the name of a river³⁶.

Much later, the word found its way into French as celadon, referring to a sea-green colour³⁷.

Natural Siennas – Umbers

Natural siennas are, fundamentally, natural ochres: iron-oxide earth pigments consisting principally of a mixture of goethite (yellow) and haematite (red). As with ochres, the predominant mineral in the mixture determines the resulting dark yellow, ochre-brownish colour³⁸.

They also contain a small percentage of manganese oxides, which contribute to their brownish hue³⁹. Umbers generally contain a higher proportion of manganese oxides than siennas.

Siennas and umbers are known to have been used in art alongside other earth pigments since the Palaeolithic era. The name “sienna”, however, derives specifically from Siena in Tuscany, Italy: Terra di Siena became Sienna⁴⁰.

Umber was traditionally used for shadows because of its darker brown colour. The word umber derives from the Latin umbra, meaning “shadow”.

Natural Sienna from Cyprus & Natural burnt sienna from France

The local mineral composition of the Cypriot source produces a sienna of exceptional quality.

We selected it for its chromatic harmony with the yellow ochres and its established reputation for quality.

In its burnt form, the French sienna is calcined to produce the historically characteristic burnt sienna.

Natural Raw Umber & Natural burnt umber from Cyprus

Depending on the natural conditions under which umber forms and the proportion of manganese oxides present, umbers can be divided into sensus lato (umber in the broader sense) and sensus stricto (umber formed under very specific conditions).

The latter are, naturally, much more limited than the former and occur only in specific locations where all the necessary geological conditions are present.

The principal source of umber in the strict sense is Cyprus. Cypriot umber has long been regarded as “by far the best pigment” because of its deep and rich colour⁴¹.

Burnt umber is produced by calcining raw umber, resulting in a darker, reddish-brown colour of equally exceptional quality.

Mineral black - magnetite

Magnetite is the naturally occurring black iron oxide; its synthetic equivalent is Mars Black.

It has been used as a pigment since ancient times and is present in the ancient Attic black glaze⁴²,⁴³ used on Classical Attic pottery from approximately the 8th to 4th centuries B.C., as well as on pottery of the Hellenistic period (4th–1st centuries B.C.).

Geologically, magnetite occurs as lenses within metamorphic schists, for example in the Adirondack region of the U.S.A. and on Kythnos in Greece⁴⁴.

The great ancient Greek philosopher Plato (427-347 B.C.) describes precisely the magnetic properties of the stone. He states that Euripides, the famous ancient Greek tragedian (c. 480–c. 406 B.C.), had named the mineral Μαγνῆτις (Magnet), while most people, as he says, called it Ἡρακλεία λίθος (“Hercules’ stone”), most probably because of its ability to attract iron:

“θεία δὲ δύναμις ἥ σε κινεῖ, ὥσπερ ἐν τῇ λίθῳ ἣν Εὐριπίδης μὲν Μαγνῆτιν ὠνόμασεν, οἱ δὲ πολλοὶ Ἡρακλείαν”⁴⁵ (“a divine force that moves you, just as happens with the stone that Euripides called a ‘magnet’ and which most people refer to as ‘Hercules’ stone’).

Natural Indian black

This pigment consists of pure natural magnetite from India. It is a deep, highly opaque black with a subtle brownish undertone.