Most inherited pearl necklaces are either cultured pearls or imitations, and a few simple checks usually point clearly one way. Real pearls, whether natural or cultured, feel slightly gritty when rubbed gently against your front teeth, show small irregularities in shape and surface, and have clean, sharp drill holes. Imitation pearls feel glassy smooth, often match each other perfectly, and tend to show flaking or chipped coating around the holes. Roughly speaking, an imitation strand sells for $5-30, a cultured Akoya strand for $100-500, and Tahitian or South Sea strands from $500 upward.
What home checks cannot do is tell a natural pearl from a cultured one. That needs an X-ray examination at a gemological lab, and it matters because natural pearl strands can be worth many thousands of dollars while cultured pearls of the same look are worth hundreds.
The three kinds of pearl
Natural pearls
A natural pearl forms by chance inside a wild oyster or mussel, with no human help. Before the 1920s almost all fine pearls were natural, and they were enormously expensive. Today natural pearls are rare in inherited jewelry, but they do turn up in Victorian and Edwardian pieces and in old strands passed down from wealthy families. Only a lab can identify them.
Cultured pearls
A cultured pearl grows inside a farmed mollusk after a technician inserts a bead or a piece of tissue. Kokichi Mikimoto commercialized the process in Japan in the early 20th century, and by the 1950s cultured pearls had replaced natural ones in most jewelry stores. Cultured pearls are real pearls with real nacre, the layered material that gives a pearl its glow.
Imitation pearls
Imitations are glass, plastic or shell beads with a pearly coating. They range from cheap plastic to well made glass pearls:
- Plastic: very light, warms almost instantly, and the coating peels easily.
- Glass: heavier, often with a lacquer or fish scale based coating. Many 1930s to 1960s costume strands are glass.
- Majorica: a well known Spanish brand of man-made pearls with a glass core and a thick lustrous coating. They are good imitations, usually sold with a clasp or tag marked Majorica, and sell for roughly $30-150 used.
- Shell pearl: beads ground from shell and coated. Common in modern fashion jewelry.
Imitation is not an insult. Plenty of beloved family strands are good glass pearls from a department store. They just do not carry the value of cultured pearls.
Home checks that point in a direction
The tooth test
Rub a pearl gently along the edge of your front teeth. Real pearls feel slightly gritty or sandy because nacre is built from tiny overlapping crystals. Imitations feel smooth and slippery. It is the most widely used home check and is usually right, but some high quality imitations are given a faintly textured surface, and very worn real pearls can feel smoother than expected. Clean the pearl first and be gentle.
Surface and shape
Look closely in daylight, ideally with a magnifying glass:
- Real pearls show tiny bumps, ridges or spots, and slight differences in shape and color from pearl to pearl.
- Imitations often look perfectly round, perfectly matched and perfectly uniform.
- Freshwater pearls are often slightly oval, rice shaped or potato shaped.
- Akoya pearls tend to be round and between 6 and 8 mm.
Drill holes
The drill holes are among the most useful clues:
- Real pearls usually have small, crisp holes with clean edges. Sometimes you can see the line between bead nucleus and nacre layer just inside the hole.
- Imitations often show chipped, flaking or bubbled coating around the hole, a ridge of built up coating, or a glass or plastic core showing through.
Weight and temperature
Real pearls feel slightly heavy for their size and cool to the touch at first, then warm slowly. Plastic imitations are light and warm quickly. Glass imitations can feel heavy and cool, so weight and temperature only separate real pearls from plastic, not from glass.
Rubbing two pearls together
Real pearls rubbed gently against each other feel a little rough and may leave a fine powder that wipes off. Imitations glide. This can scratch fine pearls, so it is best left to a jeweler.
The clasp and the stringing
The clasp often says more than the pearls:
- A gold clasp stamped 14K, 18K, 585 or 750 is a good sign the strand was valued when it was made. See our guide on how to tell if gold is real.
- A Mikimoto clasp usually carries the company's stamped logo together with a metal mark such as K14, K18 or SILVER, and often a small pearl set in the clasp. Mikimoto is one of the most copied names in pearls, so a logo is a reason to look closer, not proof on its own.
- A base metal or plated clasp leans toward an imitation or a modest freshwater strand, although clasps are sometimes replaced.
- Knots between each pearl suggest a fine strand strung by a jeweler. Imitation strands are often strung without knots.
Akoya, freshwater, South Sea and Tahitian
Each type of cultured pearl has its own look and value range:
- Akoya: Japanese and Chinese saltwater pearls, usually white or cream with rose or silver overtones, round, 6-8 mm, with sharp luster. This is the classic grandmother's strand.
- Freshwater: mostly Chinese, grown in mussels, often oval or off-round, in white, peach, pink and lavender. Very common and the most affordable.
- South Sea: large white or golden pearls from Australia, Indonesia and the Philippines, usually 9-15 mm. Expensive.
- Tahitian: dark pearls from French Polynesia, in gray, green, peacock and aubergine tones, usually 8-14 mm. Black pearls that are very uniform and jet black may be dyed freshwater pearls instead.
Typical values
| Pearls | Approximate resale value |
|---|---|
| Plastic or coated glass costume strand | $5-30 |
| Majorica or similar quality imitation strand | $30-150 |
| Freshwater cultured strand | $20-150 |
| Akoya cultured strand, 6-7 mm | $100-500 |
| Mikimoto Akoya strand with original clasp | $500-3,000 |
| Tahitian or South Sea strand | $500 upward, often thousands |
| Natural pearl strand with a lab report | Thousands to far more |
Size, luster, surface, shape and matching drive the price within each tier. Luster, the sharpness of reflections on the surface, matters most. A strand of dull, chalky pearls is worth much less than a bright one of the same size.
Condition problems to look for
- Worn or peeling nacre: shows as dull patches or the bead nucleus showing through. Lowers value sharply.
- Yellowing: common on old Akoya. Mild yellowing is normal, heavy yellowing hurts value.
- Stretched or dirty silk: easy to fix. Restringing costs roughly $30-100 and is normal maintenance.
- Damage from perfume, hairspray or acidic skin: shows as dull or pitted spots.
- Broken or missing clasp: lowers value modestly, more on signed strands.
What a photo can and cannot show
A good photo can show shape, uniformity, luster, color, the stringing, the clasp and its stamps, and the condition of the drill holes in close-up. That is often enough to say whether a strand is consistent with cultured pearls or with an imitation, and to place it in a value tier.
A photo cannot tell a natural pearl from a cultured one, cannot measure nacre thickness, and cannot detect dyes or treatments for certain. The photos that help most are a close-up of the drill holes with a few pearls slid apart on the string, a sharp close-up of the clasp stamps, and the whole strand laid flat in daylight next to a ruler.
The professional route
If the strand passes the tooth test, has a gold clasp, or came from a family that owned fine jewelry, take it to a jeweler who handles pearls or to a gemologist. For an old strand that might be natural, a lab report from GIA or a similar gemological lab is worth the fee before selling, since it can change the value by an order of magnitude. Pearls found alongside costume pieces may also include collectible signed costume jewelry, which our costume jewelry guide covers.