Pearls: cultured, natural or imitation, and what sets the price

A pearl is the only gem grown inside a living animal, and it begins as a problem. In The history of pearls, written by Åse Anderson for The Jewellery Editor on 31 December 2015, the mechanism is plain: "A pearl is formed when an irritant, such as a parasite or piece of shell, becomes accidentally lodged" inside the mollusc, which answers by coating it in "a crystalline substance called nacre". Almost every pearl on sale today is made that same way, except that the irritant "is implanted in the oyster rather than entering it by chance".

I have made jewellery by hand in London for 22 years, from a stall on Portobello Road to counters in Liberty, Selfridges, Harvey Nichols and Harrods. Pearls have been on my bench for most of it, and they are the material customers ask about most nervously, usually because somebody once told them a pearl was fake when it was not.

Three words worth getting straight

Natural means a pearl formed with no human involvement at all. Vanishingly rare, and mostly in auction rooms.

Cultured means a real pearl, grown by a real mollusc, where the irritant was placed deliberately. That is almost all pearl jewellery in the world, at every price.

Imitation means glass, resin or plastic with a coating sprayed on, often sold as faux or shell pearl. A lovely finish, and not a pearl. So cultured on a listing means real. Faux does not. Mine say genuine pearl, which is the phrase to look for.

The 4 things that set the price

Lustre is the one that matters and the one nobody mentions. It comes from the thickness of the nacre, which Claire Roberts' conch pearls piece for The Jewellery Editor, 26 February 2018, calls "the substance that gives traditional pearls their iridescent lustre". Thin nacre reads flat and chalky. Thick nacre has a depth to it, almost wet, and you can see which is which the moment 2 pearls sit together.

Shape. A properly round pearl is dearest because it is rarest. Anderson notes that "Baroque" is the term for pearls that are non-symmetrical, and a baroque pearl is not a second rate round one. It is its own thing, and usually the more interesting piece to wear.

Surface. Small marks and faint ridges are normal. They do not make a pearl poor quality, they make it a pearl.

Size is measured in millimetres, and price climbs steeply rather than steadily, because bigger pearls take longer to grow.

Pearls, Anderson writes, "can be found, or cultivated, in freshwater or saltwater", and cultured freshwater pearls come mainly from China. Freshwater is what sits in most everyday pearl jewellery, mine included, and it is why a genuine pearl piece can cost £30 rather than £3,000.

The piece I would start with

The Brigette Pearl Disc Necklace is what I reach for when somebody wants a pearl that is also theirs: a genuine pearl beside an 18mm disc I engrave with an initial, a word or a name. £200 in sterling silver, £250 in gold vermeil or rose gold vermeil, £850 in 9kt solid yellow or white gold.

I notice people buy a pearl for a reason they do not say out loud. Almost always a marker: a birth, a wedding, a year that was hard. The engraving is where that goes, and nobody else need read it.

Two other ways in

For pearls you can wear on a Tuesday, the Pearl Bracelet is genuine pearls on a stretch with a single initial charm among them, £80 in sterling silver and £95 in gold vermeil. There is no length to guess, so it is the easiest pearl thing to buy for somebody else.

Lower down, the Initial Pearl N Necklace is £30, silver plated, with a genuine pearl and cubic zirconias, a 17.5mm pendant on a 45cm box chain. Ready made rather than made to order, so it arrives quickly.

If the name matters more than the letter, the Audrey Pearl Name Bracelet sets a cluster of pearls behind a scripted name, £125 in sterling silver, £145 in gold vermeil, £390 in 9kt solid yellow gold, in 3 lengths. The Chain Guide settles which. Pearls run through the bridal collection for the obvious reason and through the Christmas gift guide for the less obvious one: a pearl suits somebody whose taste you cannot guess.

The pearls already in your house

Most people reading this own pearls they never wear, in 1 of 4 states. An inherited strand on a thread gone slack and grey. One pearl earring, the other long gone. A pearl set in a ring that fits nobody. A brooch.

None of it is scrap and none of it has to stay in the drawer. Second Life Jewellery is the remodelling and resetting service I run from the London studio. Send a photograph, I tell you what can be done and what it would cost, no obligation and no charge. The pearls stay yours. The shape changes. If there is unworn gold in the same box with no stones worth keeping, recycling your jewellery is the other route, and it comes back as credit.

The second life is the real one.

If you have an inherited pearl piece you never wear, send me a photograph through Second Life Jewellery. Anna Lou x.

Questions I get asked

Are cultured pearls real pearls?

Yes. A cultured pearl is grown by a living mollusc out of real nacre, exactly as a natural pearl is. The only difference is that the irritant at its centre was placed there rather than arriving by accident. The word to be wary of is not cultured, it is faux.

How can I tell whether a pearl is genuine?

The listing should tell you, and if it does not, ask. Beyond that, genuine pearls are never identical to one another, so a strand where every pearl matches perfectly is usually imitation, and real pearls feel cool and slightly heavy for their size. A jeweller can settle it in seconds, which is a reasonable thing to ask of one.

I have my grandmother's pearls and never wear them. What can I do?

Send a photograph to Second Life Jewellery and I will tell you what it could become, free and with no obligation. Pearls often remake well into something worn daily rather than a strand kept for best. If it is a question of length rather than design, the Chain Guide will tell you what sits where.