Stone Rings: Measuring Your Finger, Sizes and Care
How to measure your finger, read a ring size, choose a stone hard enough for a ring and care for it. Practical tips and French size reference points.
Key points
| French size | Equal to the inner circumference of the ring, in millimetres (52 = 52 mm) |
|---|---|
| Diameter | Circumference divided by 3.14 (52 mm is about 16.6 mm) |
| Standard | ISO 8653 (ring size measurement) |
| Recommended stone | Hardness of 7 or more for daily wear |
| Best time to measure | End of the day, at normal body temperature |
| To avoid | Hot water, household products, sport, ultrasonic cleaners |
Stone rings: what is special about them
The ring is the jewellery piece most exposed to scratches and knocks: the hand touches everything, all the time. For a ring, the choice of stone and setting is therefore even more important than for a pendant. At the same time, sizing is a technical matter: a ring that is too small hurts, and one that is too large falls off.
This page is part of the stone and metal jewellery guide.
Measuring your finger
- Cut a strip of paper about 10 cm long and 5 mm wide, or use a non-stretch thread.
- Wrap it around the base of the finger concerned, without tightening it or leaving any play.
- Mark with a pen the point where the end meets the paper.
- Measure the length up to the mark, in millimetres: that is your finger circumference.
- Repeat at two or three different times of the day.
Finger size changes with temperature, time of day, exercise, salt and tiredness. Measure at the end of the day, when you are neither very cold nor very hot. If the knuckle is wider than the base of the finger, the ring must pass over it: take the intermediate size. For a wide ring (over 6 mm), choose one size up, as it fits more tightly.
Reading sizes
In France, the ring size corresponds in principle to the inner circumference of the ring, in millimetres: a size 52 ring measures 52 mm around the inside, or about 16.6 mm in diameter. The ISO 8653 standard defines how ring sizes are measured; in its 1986 version, the size corresponded to the inner circumference in millimetres. Here are some calculated equivalents (diameter = circumference divided by 3.14):
| Size / finger circumference | Inner diameter |
|---|---|
| 48 mm | about 15.3 mm |
| 50 mm | about 15.9 mm |
| 52 mm | about 16.6 mm |
| 54 mm | about 17.2 mm |
| 56 mm | about 17.8 mm |
| 58 mm | about 18.5 mm |
| 60 mm | about 19.1 mm |
US and British sizes do not match French sizes perfectly; conversion tables are approximate. Where possible, rely on a measurement in millimetres or on a ring sizer (a set of reference rings).
Which stone for a ring?
House dust contains quartz, which has a hardness of 7. A softer stone will therefore gradually scratch on contact with surfaces. For a ring worn every day, aim for 7 or more; for an evening ring, softer stones are acceptable.
| Use | Suitable stones |
|---|---|
| Every day (hardness 7 and above) | Quartz, amethyst, citrine, agate, jasper, garnet, tourmaline, topaz |
| Occasions (hardness 5 to 6.5) | Labradorite, moonstone, amazonite, tiger's eye, obsidian |
| Rarely worn (under 5) | Turquoise, malachite, howlite, amber, selenite, pearl |
The setting matters too: a bezel setting protects the edges of a fragile stone better than a prong setting.
Setting materials
- 925 silver: classic; it tarnishes over time (see silver, steel, brass).
- Stainless steel: strong and does not tarnish; harder to resize.
- Brass or plated metal: affordable; the plating can wear faster on a ring.
Many rings sold online are adjustable (open at the back): convenient for a gift, with slightly less precision.
Care
- Take the ring off for housework, washing up, gardening, sport and swimming.
- Apply creams and perfumes before putting it on.
- Clean with lukewarm water and mild soap, using a soft brush for hard stones. Avoid ultrasonic baths, which can damage cracked or treated stones.
- Store it alone, in a box or a small pouch, so it does not get scratched.
- Have the setting checked every year: a loose claw means losing the stone.
See also caring for your stone jewellery.
Avoiding surprises
- Dyed or glued stones: a stone simply glued into a setting can fall out. Dyes can rub off onto the finger.
- Glass: some low-priced stones are glass.
- Ring too tight: if the finger swells, remove the ring at once; do not keep it on if the finger becomes red or painful.
- Resizing: a jeweller can enlarge or reduce a silver ring, but it is difficult for steel and risky for plated rings.
How to choose
Measure carefully, choose a stone hard enough for how you will wear it, and prefer a setting that protects the stone. If you are giving a ring without knowing the size, choose an adjustable design. Find our rings in the rings section.
Frequently asked questions
How do I find my ring size?
Measure the circumference of your finger in millimetres with a strip of paper or thread, at the end of the day. In France, the size corresponds to this finger circumference.
Why is my ring too tight in summer?
Fingers swell with heat and salt. Measure at different times of day and, if in doubt, choose the larger size.
Is a moonstone suitable for a ring?
It can be, for an evening ring, but it scratches easily and is sensitive to knocks (hardness 6 to 6.5, with cleavage). A bezel setting protects it better.
Can a ring be enlarged?
A jeweller can do this for silver, and sometimes for gold. It is harder for steel and risky for plated rings.
Can a stone ring be cleaned in an ultrasonic bath?
Not without a professional's advice: ultrasonic cleaning can worsen cracks in fragile or treated stones.
Also read
The meanings mentioned belong to tradition and symbolism. They are neither promises of results nor medical advice. Back to Guide to stone jewelry.