Palo Azul or lignum nephriticum (Latin for "kidney wood") derives from two species of tree, the Narra (Pterocarpus indicus) and the Mexican kidneywood (Eysenhardtia polystachya).
In the Nahuatl language Palo Azul was known as the coatli, coatl, or cuatl (snake water) or tlapalezpatli (blood-tincture medicine). It was traditionally used by the Aztecs as a diuretic.
The wood is capable of turning the colour of water into beautiful opalescent hues that change depending on the angle of light and is one of the earliest known records of the phenomenon of fluorescence. Due to this unique property, it became popular in Europe from the 16th to the early 18th-century. Drinking cups made from Palo Azul were given as gifts to royalty. Water mixed with lignum nephriticum extract were drunk from the cups and thought to contain excellent medicinal properties.
Palo Azul dye
The peculiarity of Palo Azul developing a characteristic fluorescence when infused is due to the presence of dihydrochalcones, molecules classified within the flavonoid family. Palo Azul contains alkaloids, tannins, sugars, quinones and flavonoids.
Botanical name: Eysenhardtia polystachya
Common names: Palo Azul / Kidneywood
Primary dyestuff: Wood
Class of dye: Flavonoid / ellagic tannin and suitable without a mordant
Light and wash-fastness: High
Colour: From a butter to rusty mustard yellow. Achieves a lovely dusty olive with the addition of iron
pH sensitivity: Stable
Dye bath method: Suitable for cold and hot dyeing
Recommended quantity of dye:
30% WOF bark
Swatch: Organic linen, habotai silk, peace silk, bamboo silk, cotton-silk, and bamboo jersey. Samples dip dyed into modified pH solutions for 5 mins. Colours achieved for reference only and we encourage you to experiment further.