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Organic Gems Part III: Ivory alternatives

Ivory is a biological gem material used by humans for thousands of years, with early artefacts including carvings and jewellery dating back 32,000 years. However, due to ethical concerns, possession and import of modern elephant ivory harvested after 1975 is an offence in Australia.

The use of ethical alternatives has become increasingly popular, including imitants, vegetable ivory and fossil ivory.

Ivory is composed of dentin, also spelled dentine. This is a whitish yellow and moderately hard tissue of the continuously growing teeth (tusks) that belong to certain species of mammal. Elephants are the most well-known source, but ivory may also come from walrus, hippopotamus, sperm whale, narwhal, dugong and various species of ungulates such as the boar and the warthog.

The opaque material is relatively soft without physical constraints that may arise in other crystalline gem materials. Fine details can be captured by skilled artisans, making it ideal for carvings. It is often used in antique artworks, musical instruments, jewellery and other personal and decorative items.

Elephant ivory is recognised as the principal ivory of commerce, and is associated with the illegal poaching of threatened species of African and Indian elephants. Fossil elephant ivory comes from the now-extinct woolly mammoth or American mastodon. Whilst rare, it is considered an ethical alternative, with large and well-preserved specimens attracting great value.

"While elephant ivory is a scarce organic gem associated with much global conflict, vegetable ivory has provided the market with an attractive alternative"

The legalities and ethical conflict surrounding elephant ivory has led to a market flooded with imitations including glass, plastic and organic alternatives.

The corozo or tagua palm from Central America and northern South America is a long-used and commercially available source of vegetable ivory. A sustainable and effective imitation of animal ivory, vegetable ivory is derived from the large nuts of these trees, as well as several other species of palm found in Africa and the South Pacific.

The central part of the nut is a dense white material that, once dried, can be easily carved and polished to leave surfaces with a waxy lustre – perfect for carving figurines and other aesthetic objects. It was historically used to make buttons, chess pieces and dice.

Bone, sourced from the long bones of large animals or the antlers of deer and moose, is also used as an ivory imitant. It can be distinguished from ivory by its porosity, along with its bright whiteness in contrast to the yellowish hue of ivory – although in some cases it is stained to appear less bright.

Ivory can be easily distinguished from its imitants by careful visual examination with a 10x hand lens. Elephant ivory is characterised by the identification of ‘Schreger lines’, sometimes referred to as ‘engine turning’, a pattern visible on the surface or cross section of the tusk. This pattern is a result of the internal structure of dentinal tubes.

Plastic ivory imitants lack these Schreger lines, and are much lighter than true ivory. They may also show gas bubbles or mould marks. Glass imitants are largely identified by coldness, compared to the soft warmth of animal ivory.

While elephant ivory is a scarce organic gem associated with much global conflict, vegetable ivory has provided the market with an attractive alternative that can allow for creative expression without threatening harm to Earth’s remaining wildlife.











ABOUT THE AUTHOR
Stacey Lim

Contributor • Registered GAA Gemmologist & Valuer


Stacey Lim FGAA BA Design, is a qualified gemmologist and gemmology teacher/assistant. She is a jewellery designer, marketing manager and passionate communicator on gemmology. For information on gemstones, visit: gem.org.au

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Tuesday, 16 July, 2019 10:01pm
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