“Are cultured pearls real pearls?” is a fair question with a precise answer, and the answer depends on what “real” is being asked to mean. A cultured pearl is grown inside a living mollusk, and the nacre that coats it is the same kind of material a natural pearl is made of. But in the United States the bare word “pearl” is reserved, by the Federal Trade Commission’s Jewelry Guides, for one thing only: a pearl that formed without human help. This page sets out those rules, what each term on a label claims, and what none of them tells you.
The four definitions
The FTC’s Guides for the Jewelry, Precious Metals, and Pewter Industries define pearls in 16 CFR § 23.19. In summary:
- Pearl: a calcareous concretion of alternating layers of lime carbonate and organic material, formed inside certain mollusks without human causation, as the result of an abnormal secretory process, for example in response to irritation from a foreign body that found its way in.
- Cultured pearl: a composite product created when a nucleus, usually a sphere of shell, is planted by humans inside the shell or in the mantle of a mollusk, and the mollusk coats it with nacre.
- Imitation pearl: a manufactured product, of any material, that simulates the appearance of a pearl or a cultured pearl.
- Seed pearl: a small pearl, as defined above, measuring about two millimetres or less.
The line between the first two is human causation. A natural pearl starts by accident; a cultured pearl starts because someone put a nucleus there. Both are then built up by the mollusk. An imitation is not grown at all.
What the word “pearl” may be used for
16 CFR § 23.20 turns those definitions into marketing rules:
- It is unfair or deceptive to use the unqualified word “pearl”, or any similar term, to describe a product that is not a pearl in the § 23.19(a) sense, that is, not a natural pearl.
- Used for a cultured pearl, the word must be immediately preceded, with equal conspicuousness, by “cultured” or “cultivated”, or by another word or phrase of like meaning.
- Used for an imitation, it must be immediately preceded, with equal conspicuousness, by “artificial”, “imitation”, “simulated” or a word of like meaning.
- Terms such as “faux pearl”, “fashion pearl” and “Mother of Pearl”, when used for an imitation, need the same kind of qualifying word.
“Equal conspicuousness” matters. A label reading PEARL in large type with “cultured” in small print beneath it does not meet the rule; the qualifier has to be as visible as the word it qualifies, and directly in front of it.
So, are cultured pearls real?
They are real in the sense that matters to most people: a mollusk made the nacre, and a cultured pearl is not plastic or glass. They are not “pearls” in the narrow legal sense, which is why US rules require the word “cultured” every time. A seller who calls a cultured pearl simply “a pearl”, or describes it as natural, is outside the Guides. An imitation is a different category again: it is not grown by a mollusk at all, whatever its surface looks like.
The Guides regulate words, not appearance. Natural, cultured and imitation pearls can look alike to the eye, and the label is often the only evidence a buyer has. Where the distinction matters, establishing which one a pearl is is laboratory work: gemmological laboratories examine a pearl’s internal structure, including by X-ray imaging, and issue a report describing it. A label is a seller’s claim; a laboratory report is a finding.
What a label does not tell you
- It is not a value. “Natural”, “cultured” and “imitation” describe how a pearl came to exist. They say nothing about size, lustre, surface, shape or matching, and this site gives no price for any pearl. Pearl values depend on all of those, and on a market, not on a formula.
- It does not name the type. Akoya, freshwater, Tahitian and South Sea describe the mollusk and the waters, not whether the pearl is cultured. The pearl size guide sets out the published millimetre ranges for each type.
- It does not give a weight. Pearls are traditionally weighed in units of their own, the momme and the pearl grain. The pearl weight converter converts them exactly, and keeps the 50 mg pearl grain apart from the metal grain of the grain converter.
Outside the United States
The rules on this page are the US Federal Trade Commission’s. Other countries set their own descriptions, and trade bodies publish nomenclature of their own. The principle, that a cultured or imitation pearl should be called what it is, is widely shared, but the exact words required differ, and this page does not summarise rules it has not read. The same caution runs through the guide to lab-grown diamonds, where the FTC takes the opposite approach and defines a diamond by what it is, not where it formed.