MOTHER-OF-PEARL

Mother-of-Pearl (also known as nacre) is an organic material primarily made of thin layers of aragonite (a form of calcium carbonate) bound together by an organic matrix. In watchmaking, mother-of-pearl is highly valued for its natural iridescence, unique visual patterns, and luxurious appeal, most often appearing in dials and decorative elements.

Properties and general characteristics

Mother-of-pearl has a silvery-white to multicoloured sheen, depending on the species of mollusc from which it is harvested. White or cream-toned mother-of-pearl often comes from pearl oysters in the South Pacific. Black or grey mother-pf-pearl may be harvested from black-lipped pearl oysters, famously found in Tahiti. Pink or golden hues can come from conch shells or certain other pearl oyster species. Each piece of mother-of-pearl is naturally unique in colour, pattern, and iridescent play of light. In some cases, it can be bleached or dyed for more vibrant or uniform hues.

Renowned in watchmaking for its aesthetic properties, mother-of-pearl is a very soft and brittle material. Thin sheets must, therefore, be handled with great care during the cutting, shaping, and polishing processes to avoid cracking. On the Mohs hardness scale, it typically measures between 3.0 and 4.0.

Restriction and sustainability concerns

While not as heavily regulated as ivory or certain endangered coral sources, mother-of-pearl may still fall under guidelines for sustainable harvesting of molluscs. Certain regions may also impose permit requirements or certifications for importing products derived from marine life. This can include shell-based materials, depending on the species’ conservation status.

Disadvantages

Due to its natural origin, mother-of-pearl has some limitations:

• It is very brittle and soft. Abrupt shocks or extreme temperature changes can cause cracks.
• Mother-of-pearl keeps its iridescent beauty over time as long as it remains sealed from direct exposure to harsh chemicals or mechanical stress.