To the average consumer, or even the average jewellery sales assistant, pearls are often known to be gloriously lustrous, covered in glittering nacre, as close to white as possible, and aiming to be perfectly round.
But pearls may take many forms, borne of a range of different sea creatures, whether bivalve or gastropod, nacreous or not.
Abalone – including Paua – pearls are one of the better-known examples of exotic pearls, given their popularity and harvest in Australia’s neighbouring nation, New Zealand.
A type of nacreous pearl, the most well-known Abalone variety displays a unique and highly recognisable multitude of blues, green, and brownish colours with high iridescence – the highest of the pearl-bearing molluscs.
Abalones may be natural pearls, forming without human intervention of any kind, or cultured with the introduction of a shell seed.
Natural Abalone pearls range greatly in size, from small seed pearls to large specimens of more than 70mm. These are often baroque in shape, and more rarely near round. The cultured blister pearls, however, typically range from 9mm through to 20mm or so.
These pearls form in the gastropod Haliotis, which differ from the more familiar pearl oysters in that they only have one shell and no pearl sac.
The Haliotis Iris is also known as the Paua shell or rainbow Abalone, and is the largest species in New Zealand, with a maximum shell size of around 18cm.
Other species include Haliotis fulgens, which produce green, blue and copper-coloured natural pearls with flecks of fuchsia; and Haliotis rufescens – a red abalone.
Across each species, Abalone pearls are rarer than the more commonly known varieties of cultured nacreous pearl.
For the gemmologist, characteristic identifying features of the various Abalone pearl species – besides their highly desired multicoloured orient – includes a botryoidal-like pattern on the surface at magnification, and a chalky greenish-yellow fluorescent reaction under long-wave ultraviolet lighting.
Leaving nacre behind entirely, the conch pearl proves there is beauty and desirability in the organic nature of pearl production, regardless of shine. Queen conch pearls are a very rare gem that has long been desired throughout history.
It is believed conch pearls have enjoyed a rich history alongside their nacreous counterparts, even symbolising a channel of communication with gods of the sea amongst the Inca peoples.
These white to brownish, salmon to pink pearls are produced in the Lobatus gigas mollusc (formally Strombus gigas) across the Caribbean.
What these pearls lack in traditional pearl lustre, they more than make up for in the highly sought-after orangish pink colours and a captivating porcelain-like lustre. Conch pearls also feature a distinctive flame-like structure that imparts a silky appearance.
Typically, these pearls are baroque in shape and most often between 3mm and 8mm, with sizes surpassing
13mm being rare.
The approximate estimate of the occurrence of gem-quality conch
pearls is one pearl in every 50,000 queen conch shells.
Pearls, in general, are always on the more delicate side of gemstone choice, and in the case of exotic pearls there
may be some extra precautions to take to ensure your treasures last a lifetime.
Abalone pearls are often hollow and therefore fragile; handle gently. Conch pearls, on the other hand, may fade or change colour if exposed to x-rays or to sunlight over long periods of time.
Care should always be taken in both cleaning and storing these organic gems.