Expert review: Drescher Éva — owner/manager of DRESCHER Jewellery®, qualified gold, silver and gemstone jewellery appraiser with professional jewellery-store management and sales experience.
If you've come across the term "mother-of-pearl" on a piece of jewellery and wondered whether it's the same thing as a pearl, it isn't — though the two are closely related. Here's what each one actually is, and how they differ.
What Is a Pearl?
A pearl is a gem that forms inside a mollusc's own tissue, not in its shell. According to the CIBJO Pearl Book, natural pearls form within a natural pearl sac inside a mollusc, without human intervention. Cultured pearls form the same way, except a technician inserts a graft — a piece of mantle tissue, a bead, or both — into the mollusc to initiate the growth of a cultured pearl sac, and the mollusc then coats the implant in nacre to grow the pearl.
What Is Mother-of-Pearl?
Mother-of-pearl is nacre — the same material that forms a pearl's nacre layers — but as the layer that lines the inside of certain mollusc shells, rather than a separate gem. According to the CIBJO Pearl Book, mother-of-pearl is the smooth, hard, iridescent coating on the inner shell surface of species including Pinctada maxima and Haliotis (abalone).
Is Mother-of-Pearl the Same Material as a Pearl?
No — a pearl is a distinct gem that forms within the mollusc's tissue, while mother-of-pearl is the nacreous layer lining the inside of the shell itself. The CIBJO Pearl Book's own terminology treats them as related but separate: a mollusc shell described as "gold-lipped" or "black-lipped," for example, is being described by the colour of its mother-of-pearl layer — a property of the shell — which, per CIBJO, usually but not always matches the colour of any pearl grown inside that same mollusc.
Why Do Both Have That Iridescent Shimmer?
Both get their shimmer, known as orient, from the same optical effect: light interference and diffraction across the thin, tightly stacked aragonite layers that make up nacre, as the CIBJO Pearl Book explains. It's the same underlying structure at work in both cases — inside a pearl, and lining a shell — just arranged around a different shape.
What Are Pearls and Mother-of-Pearl Actually Made Of?
Both are built from nacre, which is fundamentally calcium carbonate — the compound the CIBJO Pearl Book lists as a pearl's composition. Since mother-of-pearl is nacre by definition, it shares that same underlying mineral basis, even though it takes a different physical form as a shell lining rather than a rounded gem.
How Durable Are Pearls and Mother-of-Pearl?
Pearls are relatively soft as far as gems go — GIA rates them at 2.5 to 3 on the Mohs scale. GIA doesn't provide a separate mother-of-pearl hardness figure in the sources used for this article, so that specific hardness value shouldn't be extended to mother-of-pearl.
Does It Matter Which One Your Jewellery Piece Uses?
A pearl is a distinct gem, while mother-of-pearl comes from the nacreous lining of a shell, so they create different forms and visual effects in jewellery. That difference doesn't make one inherently better or higher quality than the other.
Every DRESCHER Jewellery® pearl and mother-of-pearl piece is set in hallmarked, rhodium-plated 925 sterling silver, the same standard our 925 Sterling Silver guide explains in full. If you already have a pearl piece, our Pearl Care guide covers cleaning, storage and what to avoid. Browse our pearl jewellery collection to see the range.
Sources:
- CIBJO (World Jewellery Confederation) — Pearl Book 2024
- GIA — Pearl Gem Overview