Some gemstones have an organic origin, such as amber (fossil resin), pearl, ivory, jet, fossils and fossil wood. The only organic material found in South Africa are fossils and ivory.

Although it is not an organic material any more, fossil wood is listed as an organic gem. Under specific conditions the cellular structure of wood has been preserved and replaced by silica, apatite, or calcite, forming petrified wood.

Gymnosperm wood (Araucarioxylon or Dadoxylon) of Permian to Triassic age (± 200 Ma) occurs in the Karoo Basin. Younger Angiosperm wood of Cretaceous age is found in KwaZulu-Natal Province. This material may be cut and polished. However, according to the National Monuments Act (Act 28 of 1969), no unauthorised palaeontological or archaological excavation or removal of objects/fossils is allowed. Any person who contravenes shall be guilty of an offence and be liable on conviction, to a fine not exceeding R10 000. The best-known localities include those in the
Northeastern Free State (Towns: Harrismith, Warden, Memel, Senekal) and the Eastern Cape Province (Towns: Jamestown, Dordrecht, Sterkspruit).

An organic gemstone charged with controversy and emotions, ivory is derived from mammal teeth or teeth modifications (tusks). Ivory, or correctly termed “dentine”, includes elephant, walrus and narwhal tusks, hippopotamus teeth and even the tusks of the wart hog or boar. The colour varies from white to yellowish. The structure of the different types of ivory differs, and thus serves as a means of identification. A ban on the trade of ivory has been imposed in many countries.

Ivory-three types of ivory depicting differences in structure: hippopotamus (at top), walrus(left) and elephant (right) This was the result of a world-wide drive and a meeting of the member nations of the Convention on International Trade in Endangered Species (CITES) in 1990. The African Elephant was then placed on its “most endangered” list. Since that time the price of ivory has dropped tremendously. In South Africa, herds are culled and the ivory locally utilised. Culling is done to maintain the population balance in the National park systems and reserves.