Hatton Garden is still the fastest place in Britain to get a loupe over a real opal. Within a few hundred metres you can look at Australian black opal in a dealer's tray, a Victorian opal brooch in a jeweller's window and a parcel of rough Ethiopian material on a folding table. It is not a shopping street in the usual sense — it is a working trade district — so an hour of preparation turns a frustrating afternoon into a productive one.
What follows covers where to look, what shop and fair prices actually reflect, and how to buy in person without getting caught out.
Hatton Garden, realistically
The district is compact. Hatton Garden itself runs from Holborn Circus up towards Clerkenwell Road, with Greville Street, Hatton Place and the surrounding side streets doing much of the trade work. You will find retail jewellers, trade-only dealers, repair workshops, bullion shops and a handful of second-hand jewellery businesses, all mixed together.
Most opals in the windows are set in jewellery. Loose stones live behind the counter, and often in a back room, which means you have to ask. Weekdays are busiest and best; Saturday opening varies widely, and many trade-facing offices shut at the weekend. A short phone call beforehand — "Do you carry loose opal, Australian and Ethiopian?" — saves a wasted journey.
What you will actually find
- Australian material: black opal from Lightning Ridge, white and crystal opal from Coober Pedy, boulder opal from Queensland, and the occasional Mintabie stone.
- Ethiopian opal: often crystal or near-crystal in appearance, frequently hydrophane, and generally cheaper per carat than Australian material of similar brightness.
- Antique and estate pieces: Victorian and Edwardian rings, brooches and pendants, usually in 9ct or 18ct gold with small diamonds set around the opal.
- Assembled and synthetic stones: doublets, triplets, lab-grown opal and treated material. All legitimate when they are described honestly as such.
How to ask
Plain questions work best. "Is this solid, or is it a doublet?" "Has it been treated?" "Where is it from?" A good dealer answers without flinching and will happily let you compare three or four stones side by side. Take your own 10x loupe; most dealers will lend you one, but having your own keeps you independent.
Ask to see the stone on white paper and then in daylight. Shop lighting is designed to flatter, and an opal that sings under a counter lamp can look flat at the door.
Antique markets and second-hand jewellery
For older pieces, the antique markets are worth a morning. Gray's Antique Market in Mayfair is the classic destination for antique jewellery, with weekday trading and a busy Wednesday. Alfies Antique Market on Church Street in Marylebone is another good source, and Portobello Road on a Saturday still turns up the occasional opal ring.
Two things to check here. First, crazing: fine surface cracks that spread across the stone and cannot be undone. Second, the setting. Opal is heat-sensitive, so a stone that has been re-polished or re-set carelessly, or one sitting loose in a worn claw setting, is a repair waiting to happen. Ask what has been replaced and whether the piece has been restored.
UK gem fairs: what to expect
Fairs give you more opals in one room than any single shop, and the price conversation is easier. The London area and the Home Counties host long-running rock and gem shows, regional mineral and lapidary societies run their own events, and bead and jewellery fairs often include a dealer or two with decent opal stock. Dates move around, so confirm with the organiser before you travel.
A typical fair has a handful of specialist opal dealers with trays sorted by type and body tone, general mineral dealers carrying a few opal lots and rough, bead and finding stalls, and tool and book sellers. The specialists are the stalls to spend time at.
What to take
- A 10x loupe.
- A small torch, ideally with a diffuser, to look through the stone.
- A sheet of white paper, so you can judge colour against a neutral background.
- Any reading glasses you need. Opals reward close inspection.
- A budget written down before you go in.
- A phone to photograph the stone next to its label, in case you want to think it over.
What drives the price
Six things do most of the work: body tone, brightness, pattern, size, origin, and whether the stone is solid. A black opal with a dark body and a bright harlequin or broad flash pattern, clean under the loupe, sits at the top of the market. Crystal and white opal are more affordable, and boulder opal — opal naturally formed in ironstone — often offers the best value per carat because the dark backing sets the colour off without the black opal premium.
Assembled stones sit in a different bracket entirely. A doublet is a thin slice of opal glued onto a backing; a triplet adds a clear quartz or glass cap. They can look superb and are perfectly good to wear, but they are not solid opal and should never be priced as such. A dull, milky body or visible crazing drops the value sharply, whatever the seller says about it.
Buying safely at a fair
- Get the description in writing on the receipt: solid, doublet or triplet; origin if known; carat weight; and whether the stone has been treated.
- Examine it in daylight. Step outside if you can, and look at the stone on white paper.
- Check the edges and the girdle for fractures and crazing, which often start where the stone is thinnest.
- Ask about returns before you pay, and get the terms on the receipt.
- Pay by card where possible, which leaves a record and may give you a route to a chargeback if the stone is not as described. Be cautious about bank transfers to sellers you do not know.
- Buy the stone, not the story. "It came from my grandfather's collection" is not a provenance.
- Do not be rushed. If a seller will not give you ten minutes to think, walk on.
A note on stability
Hydrophane Ethiopian opal can absorb water, go cloudy and change transparency; keep it away from washing-up, swimming and long soaks. Solid Australian opal is generally stable, but avoid sudden temperature changes and prolonged dry heat. Store opals separately, wrapped, so harder stones cannot scratch them.
If you are spending serious money, an independent gem laboratory report on a significant stone is money well spent; bodies such as the Gemmological Association of Great Britain also run courses if you want to learn properly. In the UK, goods bought in person must be as described, of satisfactory quality and fit for purpose, but proving a fault is far easier with a detailed receipt. If a purchase goes wrong, Citizens Advice is the usual starting point — this is general information, not legal advice.
Your first London opal trip
Go on a weekday. Ring two or three Hatton Garden dealers in advance and say what you are looking for. Spend the morning there, then walk to an antique market in the afternoon to compare how opal behaves in older settings. Take notes on each stone: weight, body tone, pattern, price and the seller's name.
Set your budget before you leave the house, and be genuinely willing to come home empty-handed. The best opal purchases are the ones you slept on and still wanted the next morning — not the one you talked yourself into because a fair was closing and the lights were kind.
Photo: TheOtherKev / Pixabay
