Choosing gemstone jewellery: sizes, materials, nickel and care

Gemstone jewellery is chosen with your eyes, but it is worn on your skin, around your wrist and through your everyday life. Size, the material of the cord and clasp, sensitivity to metals, care: this guide gives you the benchmarks to buy a bracelet, a necklace, a pendant, earrings or a ring that will fit you properly and last.

Taking your measurements

The most common reason for disappointment with jewellery bought online is size. Ten minutes of measuring can save you a return.

The thread or paper strip method

1. Take a flexible tailor’s tape. If you don’t have one, use string, non-elastic wool thread or a strip of paper about 1 cm wide.
2. Wrap it around the part you are measuring: just below the bony point of the wrist, at the base of the neck, or around the second phalanx of the finger (the middle joint).
3. Hold it snugly without compressing: you should be able to slide one finger under the thread at the wrist and at the neck.
4. Mark with a pencil the point where the thread overlaps, unroll it and measure its length with a ruler, in centimetres or millimetres.
5. Note the figure, then compare it with the actual length of the piece given on the product page, not with an unexplained “S, M, L” size.

Bracelet: from measurement to the size to choose

Size charts sometimes give the wrist circumference and sometimes the length of the finished bracelet: always check which one you are looking at. For an elastic or bead bracelet without a clasp, add 1 to 2 cm to your wrist measurement so that it slides on without squeezing. A bracelet with large beads, several rows, or one you like to wear loosely needs a little more allowance. With an adjustable clasp, the allowance is provided by the adjustment chain.

Measured wrist circumference	Suggested elastic bracelet length (close fit to loose fit)	Usually suited to
13 to 14 cm	15 to 16 cm	Children, very slim wrists
15 to 16 cm	17 to 18 cm	Slim wrists
16 to 17 cm	18 to 19 cm	The most common size for women
17 to 18 cm	19 to 20 cm	Average wrists
18 to 19 cm	20 to 21 cm	Broad wrists
19 to 21 cm	21 to 23 cm	The most common size for men

These values are practical guidelines, not a standard: each manufacturer has its own habits, and bead size changes how the bracelet sits. For a rigid bangle, measure instead the circumference of your hand with the thumb folded into the palm, at its widest point: that is the gap the bangle must pass over.

Necklace: measuring the neck

Measure the circumference of your neck at its base, where a choker would sit. For a longer necklace, the simplest method is to lay a thread where you want the pendant to hang, then measure that thread. The length chart is in the next section.

Ring: the French ring size

In France, a ring size corresponds to the inside circumference in millimetres: a finger measuring 54 mm around is a size 54. Measure around the second phalanx, without pulling too tight, as the ring must also pass over the knuckle. If the reading falls between two marks, take the higher value, and if you hesitate between two sizes, choose the larger one. A wide band or a thick stone feels tighter than a slim band: often go up half a size or a full size.

French ring size	Finger circumference (mm)	Inside diameter (mm, rounded)
48	48	15.3
50	50	15.9
52	52	16.6
54	54	17.2
56	56	17.8
58	58	18.5
60	60	19.1
62	62	19.7

The diameter is calculated by dividing the circumference by 3.14; commercial charts sometimes round slightly differently, by a tenth or two. If you own a ring that fits you well, lay it flat on a ruler, measure its inside diameter and refer to the last column.

Bracelets, necklaces, pendants, earrings, rings

Types of bracelet

Type	How it works	Strengths	Good to know
Elastic	Beads threaded on elastic cord, with no clasp	Easy to put on, light, affordable	The elastic wears out over time; do not stretch it to slip it on
Beads on cord or non-elastic thread	Knotted thread or a lobster clasp	Neater fit, thread that lasts longer depending on quality	Requires a more precise measurement
Adjustable	Sliding knot or adjustment chain	Adapts to several wrist sizes, ideal as a gift	The sliding knot loosens with use
Bangle	Rigid hoop, often metal with a stone	Elegant, no thread to break	Chosen by the hand circumference, hard to adjust
Magnetic	Magnetic clasp or magnetic hematite beads	Can be fastened with one hand	Keep it away from magnetic-stripe cards, sensitive devices and implanted medical devices, and ask a doctor if you are concerned
Lava stone	Beads of volcanic rock, porous and light	Matte look, very light	The rock is porous: it absorbs water, sweat and scented oils, which can stain it

Necklaces: length and effect

Length	Common name	Effect on the neckline
35 to 40 cm	Choker	Sits at the base of the neck, very visible, suits open necklines
41 to 46 cm	Short necklace, “princess”	Rests on the collarbone, the most versatile length
47 to 55 cm	Matinee	Falls into the hollow of the chest, shows off a pendant
56 to 70 cm	Opera	Longer, worn alone or wrapped in two rows
80 cm and above	Sautoir (long chain)	Very long, knotted or worn wrapped several times

These names vary slightly from one brand to another: go by the centimetres, not the name. A necklace that is a little long can be shortened with a knot, an adjustable clasp or an extender chain; the reverse is impossible.

Pendants, earrings and rings

• Pendants: check the height (including the bail), the weight and the strength of the bail, the small loop that links the stone to the chain. A heavy stone on a fine chain puts strain on the link. A pendant made from a freeform raw or polished stone varies from piece to piece: photographs and dimensions matter more than the name.
• Earrings: the sensitive point is the post or hook, which stays in contact with a pierced ear for hours. Look at what they are made of. Prefer light stones for earrings, and check the fastening (butterfly back, hinged hook, clip).
• Rings: a stone ring is exposed to knocks and friction. Soft stones scratch quickly, which is why it is worth checking hardness (see below). An adjustable ring suits a size difference of half a size, not more.

Materials: stone, glass, resin, metals

A piece of gemstone jewellery almost always combines several materials: the beads, the cord, the spacers, the clasp, sometimes a pendant. Each may be different, and each should be described. A reliable product page specifies the stone, the bead size in millimetres, the cord and the clasp.

Material	What it is	What to look for
Natural stone	Mineral or rock extracted, then cut and polished; each bead is slightly different	The exact name of the stone, its origin if stated, and any mention of a tint or treatment
Glass	Glass bead, sometimes imitating a stone	The listing should say “glass”; it is honest to sell it as such, but it is not a natural stone
Resin, acrylic	Plastic material, light	Very light and brightly coloured, sensitive to heat and solvents
Brass	Copper and zinc alloy, often gold-coloured	May tarnish or leave a greenish mark on the skin; the plating wears away
Stainless steel	Iron alloy resistant to rust	Common grades contain nickel built into the alloy; the reaction depends on the person (see the next section)
Plated (gold, silver)	Base metal covered with a thin layer of a precious metal	The thickness of the layer: the thinner it is, the faster it wears
925 silver	Alloy containing 92.5% silver, the rest mostly copper	The “925” engraved or hallmarked, not just the word “silver”

What “plated” means

A plated piece is made of a base metal (brass, steel or zinc depending on the case) covered with a thin film of another metal, often gold or silver. It is not solid precious metal. The layer is measured in microns (a micron is a thousandth of a millimetre): the thicker it is, the longer the finish holds. According to several specialist websites, the term “silver-plated” implies a layer of at least 10 microns, and vermeil (925 silver covered with gold) a gold layer of at least 5 microns. These thresholds are cited by commercial sources: ask the seller for the stated thickness if it matters to you. The words “gold-tone” or “silver-tone”, without further detail, do not guarantee any thickness.

What “925 silver” means

“925” is the fineness of silver: 925 parts out of 1,000, that is 92.5% pure silver, alloyed with another metal (most often copper) to harden it. It is also called sterling silver. In France, hallmarks are compulsory for silver items weighing more than 30 grams; below that, a marking is common but not always present. On imported jewellery, “925” is often engraved in full. Be careful: the Minerva head alone is not enough, because depending on the figure next to it, it can indicate a fineness of 800 parts per thousand. A “silver” piece with no mark at all should lead you to ask the seller. Silver darkens naturally with air and perspiration: this is a sign of real silver, not a defect, and it can be cleaned.

Hardness: how well does a stone resist?

Mineralogists measure resistance to scratching on the Mohs scale, from 1 (very soft) to 10 (diamond). The softer the stone, the more easily it scratches or dulls. These figures are typical values and vary between varieties.

Stone	Mohs hardness (approximate)	For a ring or everyday wear
Quartz, amethyst, tiger’s eye, rock crystal	about 7	Well suited
Labradorite, amazonite, moonstone	about 6 to 6.5	Acceptable; avoid knocks
Hematite, lapis lazuli, turquoise, obsidian	about 5 to 6	Better as a pendant or a bracelet worn with care
Malachite, howlite	about 3.5 to 4	Fragile; protect from water and acids
Selenite	about 2	Very soft, not suitable as everyday jewellery

Allergies and nickel

Nickel is one of the most frequent causes of contact allergy: it causes redness, itching or eczema wherever the metal touches the skin. Sensitisation develops gradually and, once established, is generally long-lasting. In Europe, the REACH regulation governs objects intended to stay in direct and prolonged contact with the skin, jewellery included: they must not release more than 0.5 microgram of nickel per square centimetre per week, measured according to test standards. The rule limits the release of nickel, not its presence: an alloy may contain nickel and still comply.

This rule offers protection, but it does not guarantee that no piece of jewellery will ever cause a reaction in someone already sensitised. Inspections by the French authorities on costume jewellery have, moreover, found non-compliant products: it is better not to rely on a low price alone.

• If your skin already reacts to nickel, read the product listing: clasp, chain, earring post and ring hoops are the metal parts in contact with the skin.
• Ask the seller for the composition of these parts if it is not written down. Jewellery without declared nickel is not necessarily nickel-free, but a precise answer is a good sign.
• The stone is not the cause: it is the metal. An elastic bracelet with no metal clasp rarely causes this problem.
• Perspiration, heat and friction increase the release of metal. In summer, reactions are more frequent.
• At the first sign of redness or itching, take the piece off. If a reaction persists, see a doctor or dermatologist: this guide does not replace medical advice.

Cords, clasps and drilled beads

The beauty of the stones counts for nothing if the cord breaks at the first movement of your arm. The quality of a bracelet lies in its invisible details.

The cord

• Elastic: choose a thick cord of good quality. A cord that is too thin cuts on the edge of the drilled hole. Elastic ages with heat, sun, perfume and sweat: plan to replace it one day.
• Non-elastic cord (braided nylon, coated metal cable, waxed cord): more stable, it bears the weight of large beads better, but it does not stretch, which is why measuring accurately matters.
• A tight knot, tucked inside a bead, and beads that line up neatly are good signs.

Clasps

• Lobster clasp (spring clasp): secure and common on necklaces.
• Toggle or screw clasp: more discreet; check that it locks.
• Magnetic clasp: convenient, but keep it away from sensitive equipment, and make sure it does not open after a knock.
• For earrings: hooks, posts and butterfly backs are the parts in contact with the skin.

Drilled beads

A stone bead is drilled through its centre. A clean hole, without chips on the edges, and beads of even diameter protect the cord. When you hold the bracelet up to the light, you should see round beads threaded with no play. Small variations in colour, veining and shape are normal for a natural stone: this is not a defect but proof that the material has not been moulded.

Choosing by colour and symbolism

In tradition, each stone is associated with meanings, colours, seasons or stages of life. These associations come from ancient beliefs and current practices; they are not based on scientific evidence and are neither a treatment nor a promise. You can use them as an invitation to choose a stone that speaks to you.

Colour	Common stones in jewellery	Traditionally associated with
Purple	Amethyst	Calm, serenity, reflection
Pink	Rose quartz, rhodonite	Tenderness, love, gentleness
Green	Aventurine, jade, malachite, amazonite	Luck, growth, harmony
Blue	Lapis lazuli, sodalite, aquamarine, dyed howlite	Communication, clarity, peace
Yellow and orange	Citrine, tiger’s eye, carnelian	Energy, confidence, momentum
Black and dark	Obsidian, onyx, black tourmaline, lava stone	Grounding, protection, calm
White and iridescent	Moonstone, rock crystal, labradorite	Intuition, light, renewal
Red and brown	Red jasper, garnet, hematite	Vitality, courage, grounding

The simplest approach is to follow your own taste: a colour that suits you, a shape that is comfortable, a bead size you enjoy seeing on your wrist. To explore stone by stone, see the gemstone glossary.

Wearing, layering and choosing your wrist

Wearing several bracelets

Stacking bracelets is popular. A few guidelines: vary the bead diameters (for example 4, 6 and 8 mm) for a lively effect; keep the colours coherent (warm tones together, cool tones together); alternate matte and shiny beads; do not go beyond three or four bracelets if you have a slim wrist. Avoid stacking a soft-stone bracelet against a metal bracelet: they rub against each other and get damaged.

Mixing metals

Gold, silver and copper tones: mixing them is now widely accepted. The trick is to show each metal at least twice (two gold pieces, two silver pieces), or to unite them all with a piece that combines both. Warm tones (gold, copper) flatter golden skin; cool tones (silver) suit fair skin, but this is a matter of preference, not a rule.

Left wrist or right wrist?

There is no absolute rule. According to some lithotherapy traditions, the left wrist is the one that “receives” and the right the one that “gives”; other traditions reverse this or make no distinction at all. These are interpretations, not established facts. Choose the wrist that is most comfortable for you: many people wear the bracelet on the non-dominant hand, so that it gets in the way less when writing or typing.

Care and storage

1. Take your jewellery off before showering, bathing, swimming, going to the sea, doing housework and exercising: hot water, chlorine, salt and household products damage cords, plating and some stones.
2. Put it on last, after cream, perfume and hairspray, and take it off first. Cosmetics dull stones and wear down the cord.
3. Clean dry with a soft cloth. If it is dirty, a barely damp cloth is enough, then dry it straight away. Do not use abrasive products or an ultrasonic bath for threaded beads.
4. For silver that darkens, use a suitable polishing cloth; avoid it on porous or fragile stones.
5. Store each piece flat or hung, in a fabric pouch or a separate compartment: hard stones scratch soft ones, and chains get tangled.
6. Keep them out of direct sunlight, bathroom humidity and heat, which fade some colours and tire the cord.

To purify your stones symbolically or “recharge” them according to tradition, see the guide to purifying and recharging stones: some methods (water, salt, sunlight) are not suitable for every piece of jewellery, so check the stone and the material of the cord before you try them.

Jewellery and water, sport, sleep

Situation	Careful advice
Shower, bath, swimming pool, sea	Take the piece off: hot water, chlorine and salt wear down the cord, dull the metals and damage delicate stones
Sport	Take it off: impact, sweat and friction; a bead can crack and a cord can give way mid-movement
Sleep	Take it off: the cord can catch or break, and a long necklace can be uncomfortable; for a child, it is a safety matter
Crafts, gardening, housework	Take it off: dust, products and knocks
Travel	Keep it in a separate pouch, not loose in your bag

For children, choose pieces without small detachable parts and keep an eye on them: a swallowed bead is dangerous.

Giving jewellery as a gift

• Size: if in doubt, choose an adjustable bracelet (sliding knot or adjustment chain), a necklace with an adjustable clasp, or a ring that can be exchanged. You can discreetly estimate the wrist circumference from a bracelet or watch the person already wears.
• Tastes: observe what the person already wears (gold or silver, discreet or bold) and their favourite colours. A birthstone, a favourite colour or an initial are simple ideas.
• Sensitive skin: if the person is allergic to certain metals, choose a piece without a metal clasp or specify the composition.
• Symbolism: give it as a nod (“this stone is associated with gentleness”) rather than as a remedy or a guaranteed lucky charm.
• Packaging: a pouch or a small box, and a card with a few words about the stone. Keep the receipt in case the size does not suit: see our returns and refunds policy.

Common mistakes

• Choosing a size from an “S, M, L” label without knowing the length in centimetres.
• Measuring your wrist too tightly, or in the morning in cold weather, then finding the bracelet too tight.
• Believing that a “gold-tone” or “silver-tone” piece is made of precious metal.
• Not checking the material of the clasp when you are sensitive to nickel.
• Wearing your jewellery in the shower, at the pool or during sport.
• Stretching an elastic bracelet to slip it on instead of rolling it over the hand: it loosens and breaks sooner.
• Expecting a stone to heal or to produce a result: it is a symbol, not a treatment.

Frequently asked questions

Going further

See all jewellery Delivery A question about sizing?

The meanings associated with stones belong to tradition and belief. They do not replace medical advice or treatment, and they are not a promise of any result. In case of allergy or skin reaction, take the piece off and seek advice from a health professional.