Understanding the Gold in Your Jewelry

Pure gold (24 karats) is far too soft for everyday jewelry — its hardness reaches only 2.5 on the Mohs scale, barely more than a human fingernail. This is why it is alloyed with other metals to gain strength and durability. 18-karat gold (750 parts per thousand, or 75% pure gold) is the standard for quality jewelry in Europe, while 14-karat gold (585 parts per thousand, or 58.5% pure gold) is more prevalent in North America. The nature of the alloy metals determines the color: copper yields rose gold, palladium or nickel creates white gold, and silver accentuates the classic yellow hue.

In France, the hallmark system allows you to instantly identify the purity of your jewelry. The eagle head certifies 18-karat gold of French manufacture — it is the most common hallmark in fine jewelry. The owl indicates an imported gold piece inspected by customs. The four-leaf clover denotes 9-karat gold, and the scallop shell marks 14-karat gold. These hallmarks, applied by the Bureau de la Garantie, are your first quality assurance: learn to identify them with a loupe.

There is a considerable difference between "solid gold," "gold-plated," and "gold-filled." Solid gold is a gold alloy throughout the entire thickness of the metal. Gold-plated jewelry has only a thin layer of gold (typically 3 to 5 microns) deposited by electrolysis over a base metal — it wears away quickly. Gold-filled is a compromise: a thick layer of gold (at least 5% of the total weight) mechanically bonded to the base metal, offering durability far superior to plating.

Each type of alloy reacts differently to everyday wear. Rhodium-plated white gold, for example, gradually loses its rhodium coating and may reveal a slightly yellowish tint over time. Rose gold, rich in copper, can develop a subtle patina with age — some collectors actually seek this patina for its "lived-in" character. Your skin's pH also plays a lesser-known role: more acidic skin (lower pH) accelerates the oxidation of alloy metals, which explains why some people tarnish their gold jewelry much faster than others. Diet, medication, and even stress can alter this skin pH.

Gentle Daily Cleaning

A simple bath of lukewarm water (never hot — excessive heat can weaken settings) with a few drops of mild soap — genuine Marseille soap or an unscented, neutral dish liquid — is all you need for regular maintenance of your gold jewelry. Let your pieces soak for 15 to 20 minutes to dissolve the residues of lotion, soap, and perspiration that accumulate throughout the day.

After soaking, use a soft-bristled toothbrush (a "sensitive" grade — never medium or hard bristles) to gently clean the crevices, the undersides of settings, and the links of chains. Residues lodged beneath stones are the most insidious: they form a greasy film that blocks light and makes your diamonds appear dull. Rinse thoroughly with clear, lukewarm water, then dry immediately with a clean, lint-free microfiber cloth. Residual moisture can leave limescale marks and, in the case of white gold, accelerate wear on the rhodium plating.

A gold jewel worn every day imperceptibly gathers the residues of life — lotions, perfumes, soaps. A weekly cleaning is all it takes to restore its original radiance.

The Baking Soda Method

For a deeper clean, prepare a light paste by mixing baking soda with a few drops of lukewarm water. Apply gently with a soft cloth in circular motions, without excessive pressure, then rinse thoroughly. This method is particularly effective at restoring the luster of yellow gold, but must be strictly avoided on rhodium-plated white gold, whose delicate coating could be abraded. Likewise, never use this technique on jewelry containing pearls, opals, or emeralds, whose porous surfaces would be damaged.

Ultrasonic cleaning, while highly effective for gold and diamonds, can be devastating for certain stones. Emeralds (often oiled), opals (which contain water), pearls (organic and porous), tanzanites (sensitive to thermal shock), and turquoise must never be placed in an ultrasonic bath. When in doubt, consult your jeweler before using a home ultrasonic cleaner.

What You Must Absolutely Avoid

Bleach, pool chlorine, household chemicals, and perfumes are the sworn enemies of your gold jewelry. Chlorine, in particular, can cause irreversible discoloration and weaken the alloy's structure by attacking the secondary metals (copper, silver). Always remove your jewelry before swimming in a pool or hot tub — a single prolonged exposure can be enough to irreparably damage a white gold piece.

The list of substances to avoid deserves careful attention: hand sanitizer (now ubiquitous) contains alcohols that dull gold and attack porous stones. Sunscreen deposits a stubborn greasy film in the interstices of settings. Chlorinated water and spa bromine are corrosive to alloys. Household cleaners containing ammonia or bleach are particularly destructive. Even acidic perspiration can, over time, diminish the brilliance of your jewelry.

The golden rule (quite literally) is straightforward: your jewelry should be the last thing you put on in the morning — after perfume, lotion, and makeup — and the first thing you remove in the evening. Also avoid wearing your gold jewelry during housework, gardening, cooking, or any physical activity. Even minor impacts can loosen prongs or scratch the metal.

Storage and Preservation

Storing your gold jewelry properly deserves as much attention as cleaning it. Each piece should be kept individually in a soft fabric pouch (microfiber, velvet, or silk) or a separate compartment of your jewelry box. Chains, in particular, should be clasped shut and laid flat to prevent tangles and friction between links, which create tiny cumulative scratches.

Avoid raw cardboard or untreated wooden boxes, whose natural acidity can tarnish the metal over time. Velvet- or silk-lined cases are ideal. For long-term storage, wrap each piece in acid-free tissue paper and place a small silica gel sachet inside the box to control moisture. The ideal relative humidity for storing your jewelry is between 40 and 50% — an inexpensive hygrometer can help you monitor this.

Adopt a seasonal maintenance calendar: in spring, perform a thorough cleaning and check clasps after winter; in summer, exercise extra vigilance against sunscreen and swimming; in autumn, inspect prongs before the holiday season; in winter, be mindful of hand sanitizer and dry indoor air, which can weaken organic materials like pearls. A simple quarterly reminder in your calendar is all it takes.

When to Call in a Professional

A professional ultrasonic cleaning is recommended once or twice a year for your most precious pieces. The jeweler will also inspect the condition of prongs, clasps, and settings — an essential check to prevent the accidental loss of a stone. A worn or slightly open prong is an invisible hazard: without regular inspection, you risk losing a diamond without ever noticing.

Rhodium re-plating for white gold should be performed every 12 to 18 months, depending on wear and how frequently the piece is worn. This procedure, which is quick (a few hours) and affordable (typically between $30 and $70), restores your jewelry to its original brilliant white luster. Take advantage of this visit to have all your pieces checked and request a light polish if needed. A word of caution, however: each polishing removes a minute layer of metal. For antique pieces or those with delicate engravings, overly frequent polishing can alter fine details. Limit yourself to one or two polishes per year at most.

Also consider having your most precious jewelry appraised and insured. A recent appraisal certificate (less than two years old) is generally required by insurance companies. When traveling, use the hotel safe rather than leaving your jewelry in the room, and keep it on your person during flights — checked luggage is never immune to theft or loss. When passing through airport security, place your jewelry in your carry-on before going through the metal detector to eliminate any risk of theft from the conveyor belt.

A well-maintained jewel transcends generations. The simple gestures of today are the guarantee of tomorrow's brilliance — and of the legacy you will pass on.

Care & Maintenance

Caring for gold jewelry: essential tips

Explore our worlds