Start With the Return Policy

The first question to ask isn't about the diamond — it's about what happens if you change your mind. Buying a ring online means trusting photographs and measurements, and even the most careful buyer occasionally gets it wrong. A generous, clearly written return policy is what turns a risky purchase into a safe one.

• How many days do I have to return the ring, and from which date?
• Is the refund full, or is there a restocking or handling fee?
• Who pays return postage, and must the parcel be insured?
• Are engraved, made-to-order, resized or bespoke rings excluded?

Under UK consumer law, most online purchases come with a 14-day cooling-off period starting the day the item arrives. Personalised and made-to-measure pieces are often exempt, so if the ring is being created especially for you, ask before you pay. Also check whether the window runs from delivery or from dispatch — the difference matters enormously if you're ordering weeks ahead of a proposal.

Ask About Sizing and Resizing

Ring size is the single most common reason for returns, and it's entirely avoidable. UK sizes run from A to Z and beyond, and a ring that fits one hand may be tight on the other. Fingers also swell in warm weather and shrink in the cold, so aim for a fit that slides on comfortably and needs a gentle tug to come off.

• Can this design be resized, and by how many sizes up or down?
• Is resizing free within a set period, and what does it cost afterwards?
• Will resizing risk the setting, especially on a full eternity band?
• Will they post out a free ring sizer before you order?

Some designs simply can't be adjusted — anything with stones set the whole way around, or certain tension settings. If you're between sizes, ask which way the jeweller recommends. Remember that wide bands of 6mm and above feel noticeably tighter than slim ones, so you may need to go up half a size.

Confirm Metal Purity and Hallmarking

In the UK, most precious metal items above a set weight must be independently hallmarked by an assay office. That mark is your guarantee of purity, and it's a question worth asking directly: what exactly will the hallmark show?

• Gold: 375 (9ct), 585 (14ct), 750 (18ct), 916 (22ct)
• Platinum: 950
• Palladium: 950 or 500
• Silver: 925 sterling

Ask too whether white gold is rhodium plated. Most is, to give it that bright silvery finish, and it will need replating every 12 to 24 months depending on wear. Yellow gold and platinum don't need this. Be alert to wording such as "gold plated", "gold filled" or "vermeil" — these describe a thin layer of gold over a base metal, which is a very different purchase.

Demand Certification for Gemstones

For diamonds and coloured stones, ask what documentation accompanies the gem. A stone of any real value should come with an independent report from a recognised gemmological laboratory, complete with a report number you can verify yourself.

• Is the stone natural, laboratory-grown, or a simulant such as cubic zirconia?
• What are the four Cs — carat, cut, colour and clarity?
• Is there a certificate number, and which laboratory issued it?
• Have any treatments been applied, and are they disclosed?

Treatments are common and not always a problem, but they must be declared. Heated sapphires and rubies are standard; oiled emeralds need gentler care; fracture-filled diamonds are worth far less than untreated ones. A "certificate of authenticity" printed by the seller is not the same as an independent grading report, so don't be fobbed off with a glossy card and a logo.

Request Extra Photographs and Measurements

Studio photography is lit and retouched, and it flatters a ring in ways ordinary daylight never will. Before you commit, ask for the following — a good seller will provide them without hesitation.

• A short video in natural daylight, held still and then turned slowly
• Macro shots of the setting, claws, shoulders and any engraving
• Band width and depth in millimetres, measured with callipers
• The total gram weight of the finished ring
• Stone dimensions in millimetres, not just carat weight
• A photograph of the ring worn on a hand, to judge scale

Millimetres tell you more than photographs ever can. A 2mm band reads as delicate and elegant; 4mm feels substantial and modern. A 1.5 carat round brilliant is roughly 7.4mm across, but the same weight in an oval or marquise can look considerably larger because of its length. Knowing the numbers prevents the quiet disappointment of a ring that arrives smaller than you pictured.

Ask About Care, Insurance and After-Sales

An engagement ring or wedding band should outlive the occasion it was bought for, so it's fair to ask what support comes with it.

• Does it include a valuation suitable for insuring the ring in the UK?
• Is there a warranty, and does it cover the setting, the stones and any plating?
• What cleaning is safe at home, and what should be avoided?
• Will they check and tighten claws periodically, and at what cost?

As a rule, warm water with a drop of mild washing-up liquid and a soft brush is kind to gold, platinum and diamonds. Skip the ultrasonic cleaner for emeralds, opals, pearls and treated stones, and keep every piece away from chlorine and harsh household cleaners. Store rings separately so harder stones don't scratch softer ones.

Write the answers down, or keep them in an email. If a seller is vague about returns, sizing, purity or certification, that vagueness is itself information. A good jeweller will answer every question patiently and in writing before you spend a penny — and that confidence is worth as much as the ring itself.