How can I tell a real pearl from an imitation?

Real pearls feel slightly gritty when rubbed lightly against a tooth edge, and cool to the touch. Our gemologist tests every strand before listing, including whether the pearls are natural or cultured.

Can a crazed opal be fixed?

No. The fine network of surface cracks is permanent, which is why storage and temperature matter so much with opal.

How much does restringing cost?

It is modest and it is the single best thing you can do for a strand. We restring pearls bought from us on request.

How-to & tools

Caring for pearls, opals and other soft stones

Last on, first off, and never in an ultrasonic.

Written by our in-house jewelry team · Updated August 1, 2026 · 6 min read

Strand of vintage pearls and a pearl ring resting on cream silk — Caring for pearls, opals and other soft stones

In short

Pearls, opal, emerald, turquoise, coral and amber are soft, porous or fracture-prone. Put them on after perfume and hairspray, wipe them with a soft damp cloth after wearing, keep them away from ultrasonic cleaners, heat and chemicals, and have pearl strands restrung on knotted silk every one to two years of regular wear.

Hardness is only part of the story. Pearls are soft and porous, opal holds water and dislikes sudden temperature change, and emerald is hard but heavily included and prone to fracture.

Shop the pieces: Pearl, curated and available now.

Pearls

Pearl is nacre, an organic material around 2.5 to 4.5 on the Mohs scale, which makes it softer than almost anything else in a jewelry box. Perfume, hairspray, hand sanitizer and even sustained skin acidity dull the surface.

The rule is last on, first off. After wearing, wipe the strand with a soft cloth slightly damp with plain water and let it dry flat before putting it away.

Restring on silk with a knot between each pearl every one to two years of regular wear
Knots stop the pearls rubbing and stop you losing the strand if the thread breaks
Never hang a strand to dry; the wet silk stretches
Never use an ultrasonic, steam, or any dip cleaner

Opal, turquoise, coral and amber

These are porous and absorb oils, dyes and solvents. Clean with a dry or barely damp cloth only and store away from direct heat and strong light.

Opal contains water, typically several percent by weight. Rapid drying or a hot car dashboard can craze it, and a crazed opal cannot be repaired. Many antique turquoise pieces have naturally changed color over the decades from contact with skin oils; that is age, not damage.

Emerald

Emerald is 7.5 to 8 on the Mohs scale but is usually included enough to be fragile. Nearly all emeralds, antique ones included, have been treated with oil or resin to improve clarity, which is an accepted and disclosed practice.

Ultrasonics, steam, heat and solvents strip that filler and can make the inclusions far more visible. Warm water, mild soap and a soft brush, or better still a professional clean and re-oil.

Antique gold rings with old-cut diamonds and a ruby on cream silk beside a brass ring dish — How-to & tools — from the pieces and workshop notes behind this guide.

Frequently asked questions

How can I tell a real pearl from an imitation?: Real pearls feel slightly gritty when rubbed lightly against a tooth edge, and cool to the touch. Our gemologist tests every strand before listing, including whether the pearls are natural or cultured.
Can a crazed opal be fixed?: No. The fine network of surface cracks is permanent, which is why storage and temperature matter so much with opal.
How much does restringing cost?: It is modest and it is the single best thing you can do for a strand. We restring pearls bought from us on request.

Written by our estate jewelry team and reviewed by our in-house gemologist. We have been buying and selling European antique jewelry since 1973.

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