Transparent Tavush Green Earth Pigment

Rublev Colours Tavush Transparent Green Earth is the greenish mineral celadonite—a phyllosilicate of hydrated iron potassium silicate containing small amounts of aluminum, calcium, magnesium, sodium, and numerous trace elements. It is a green mineral that resembles tiny flakes of mica or small lumps of clay. The color of celadonite varies considerably, ranging from pale green to bright green, bluish-green, olive-green, and black-green, depending on its constituent elements. Rublev Colours Tavush Green Earth is from the Idzhevanskoe deposit, Idzhevan, Tavush province of Armenia. This is a much more transparent green earth than Tavsh Green Earth.

Origin and History

The word celadonite is derived from the French word celadon, meaning sea green. It has been used in painting since ancient times, and was recently found in Roman frescoes. Restorers have proved through X-ray diffraction that the famous pigments of past centuries known as Veronese terre verte are, in essence, celadonite minerals. It was first described in 1847 on Monte Baldo, near Verona, Italy. It is one of two minerals, along with glauconite, used in making the pigment green earth.

Celadonite is almost exclusively found associated with basic-eruptive rocks in deep-marine environments. Altered basalts from ocean-bottom environments that contain celadonite have been found. Basalts containing celadonite can also be found on land, but these are usually assumed to have formed in marine environments.

Green earth pigments, also known as terre verte, form a dull green color in their dry powder. They are inorganic pigments composed of the minerals celadonite and glauconite. However, according to Anne Wall Thomas, “Green earth, or terre verte, is a mineral but not in the strictest sense an iron oxide pigment. Consequently, it cannot be classified as a product of one of the four iron ores. The presence of celadonite or glauconite, minerals of complex silicate composition, produces colors that vary from cold bluish greens to warmer yellow and olive hues. The green earths, which contain small amounts of iron along with manganese and other components, may have origins in oceanic deposits.” (Thomas, 12–3)

Anne Wall Thomas (1980). Colors from the Earth: The artist’s guide to collecting, preparing, and using them. Van Nostrand Reinhold Co.

Particle Size

The particle size composition of Tavush Green Earth is 80–85% from sub-0 to 15 microns, with the remainder ranging up to 30 microns, with only 0.1% at 30 microns and above.

Permanence and Compatibility

Green Earth is among the most permanent colors in the artist’s palette. It is compatible with all other pigments and can be used with good results in all mediums.

Oil Absorption and Grinding

This pigment is easily ground in vegetable drying oils and water. The oil absorption value (OAV) is 28 grams of linseed oil for 100 grams of pigment.

Toxicity

The pigment is considered non-toxic, but care should always be exercised when handling the dry-powder pigment to avoid inhaling dust.