What is Vegetable Ivory?

Vegetable ivory, also known as corozo or tagua, is a material obtained from the seeds of a palm tree, the Phytelephas macrocarpa, which grows in the South American rainforest. Once dried, the fruit (the endosperm of which is used) has a texture, color, and appearance very similar to animal ivory and can be easily worked and dyed.

It is used to make: mosaics, floors, wall coverings, buttons, beads, jewelry, keys, and parts of musical instruments such as bagpipes. Once an inexpensive substitute for ivory, it has regained its economic and ecological importance after the ban on elephant hunting.

The name corozo is used to refer to the fruits of a species of palm called Phytelephas macrocarpa or Hyphaene thebaica. The fruits of the former species can reach 60 cm in length and weigh up to 12 kg. Each seed is divided into six or seven parts. Each of these parts contains cells[1]. Each cell can contain 6–9 seeds the size of a pigeon egg. Freshly formed seeds contain a colorless liquid that becomes milky upon maturation due to an increase in hemicellulose.

At first glance, the seeds of this plant appear to have a uniform structure, but a careful examination with a magnifying glass reveals parallel channels filled with a more vitreous material that gives these seeds a porosity allowing them to be dyed.

The fruits of the second species consist of a single seed made of hemicellulose. The seed has a cavity in its center that limits its use and has characteristics similar to true corozo (that is, the seeds of the Phytelephas macrocarpa).

The color of corozo is similar to that of animal ivory, with which it shares other similarities:

• hardness (2.5 on the Mohs scale);
• absence of flaking;
• waxy luster;

however, the two types of ivory differ in the following ways:

• fracture: animal ivory has a splintery fracture, while corozo has an irregular fracture;
• fluorescence: animal ivory is bluish-white or yellowish, while corozo is bluish-white;
• density: animal ivory is denser (1.70–1.95 g/cm³ compared to 1.40 g/cm³ for corozo).

Because corozo is composed of cellulose, it is flammable and chars very quickly when exposed to fire.