Amber has often been imitated by other resins like copal and kauri, as well as by celluloid and even glass.
Ivory, rubber and copal are the chief exports.
Many species are rich in gums and resins; the calambac, mastic, copal, cedar, &c. Many others are oleaginous, among them, peanuts, sun-flowers, the bene seed (sesame), corozo, almond and palmachristi.
Cocoa, rice and cotton were also increasingly cultivated and the fall in the value of rubber led to a much larger collection of copal, the amount exported, 2,139 tons in 1911, being 8,719 in 1916.
The silk-cotton tree (Bombax ceiba), miomba, tamarisk, copal tree (Hymenaea courbaril) are frequent, besides sycamores, banyan trees (Ficus indica) and the deleb palm (Borassus aethiopum).
From the forests are obtained rubber, copal, bark, various kinds of fibre, and timber (teak, mahogany, &c.).
Incense was constantly used, especially the copalli (copal) well known to us for varnish; little terra-cotta censers are among the commonest of Mexican antiquities.
It is allied to copal in its nature and appearance, and is much used by varnish-makers.
Certain resins are obtained in a fossilized condition, amber being the most notable instance of this class; African copal and the kauri gum of New Zealand are also procured in a semi-fossil condition.
Gum copal is exported.
Palm-oil, palm kernels, cocoa, copal, copra, Calabar beans, kola-nuts and ivory are the principal exports.
Rubber, ebony and other timber, cocoa and gum copal, come next in importance.
Quicklime mixed with white of egg, hardened Canada balsam, and thick copal or mastic varnish are also useful for cementing broken china, which should be warmed before their application.
The presence of gum copal in considerable quantities in the superficial rocks is characteristic of certain regions.
Gum copal, ground-nuts and sesame are largely cultivated, partly for ' Numerous remains of a stone age have been discovered, both on the coast and in the hinterland.
The young trees, he states, furnish the most valuable gum, the older yielding merely a clear glutinous fluid resembling copal varnish.'
Palm oil, palm nuts, white copal, coffee, cocoa, rice, earth-nuts and timber are next in importance among the exports.
Of dye-yielding shrubs and plants camwood and indigo may be mentioned; of those whence gum is obtained the copal, acacia and African tragacanth (Sterculia tragacantha).
It was already an epis copal see, and, in the 13th century, Dominican and Franciscan monasteries were established to check the spread of Bogomilism.