Know the stone before you buy it.

We grow the diamond. We do not grade it. Every stone we set is sent to an independent laboratory, IGI or GIA, where a gemologist who has never met us measures it and writes down what they find. That report is yours, and it travels with the piece.

What is on it

• Report number: unique to this stone. Type it into the lab's website and the same report appears. If it doesn't, walk away.
• Laser inscription: the same number etched microscopically on the girdle, the thin edge of the stone. You can see it under a loupe. It ties the paper to the diamond.
• Measurements and weight: to a hundredth of a millimetre and carat.
• Cut, colour, clarity grades: the 4Cs, assessed by someone with no reason to flatter the stone.
• Plotting diagram: a map of any internal marks, so you can find them yourself.
• Growth method: the report states that the stone is laboratory-grown and, usually, that it was grown by CVD. We think this line is a point of pride, not fine print.

IGI or GIA?

Both are respected. IGI has graded lab-grown diamonds for longer and issues full colour and clarity grades on them; GIA introduced full grading for lab-grown more recently. We use both. The report that matters is the one that matches the inscription on your stone.

The one line to read first: the report number. Check it online before you check anything else.

The science

A lab-grown diamond is a diamond. Same carbon, same crystal lattice, same hardness, same refractive index, same fire. Put one beside a mined stone of the same grade and no jeweller can tell them apart by eye; it takes laboratory equipment to see the difference in growth pattern. This is not a marketing claim; it is the reason IGI and GIA grade them on the same scale.

The difference

Origin. One formed over a billion years under the earth. One formed over a month inside a reactor. That is the whole of it. What you decide that difference is worth is personal, and we would rather you decide it with the facts than with someone's sales pitch.

Price

Lab-grown diamonds cost a fraction of mined stones of the same grade, and the gap has widened every year. That is not because they are worse. It is because growing a diamond is a process that gets cheaper with scale, and mining one does not. Anyone selling a lab-grown stone at near-mined prices is charging you for their overhead, not their diamond.

Resale

Be careful here. Mined diamonds do not hold retail value either: most resell at a steep discount. Lab-grown stones resell for less still, because new ones keep getting cheaper. If you are buying a diamond as an investment, buy something else. If you are buying it to wear for forty years, this is the better stone for the money by a wide margin.

Ethics

No mine, no displaced community, no question of where it came from, because it came from us. We also think the environmental argument is often overstated on both sides; a reactor uses real electricity. What we can say plainly is that we know the origin of every stone we sell, and very few jewellers can.

Questions to ask any seller: Is it certified? By whom? Can I check the number? Where was it grown? If the answer to the last one is a shrug, keep looking.

A diamond cannot be scratched by anything except another diamond. That is the good news. The bad news is that it attracts grease like nothing else, and a week of hand cream and washing-up is enough to dim it noticeably.

Cleaning at home

Warm water, a drop of dish soap, and a soft toothbrush. Ten minutes soaking, a gentle brush around the back of the setting where oil collects, rinse, and dry with a lint-free cloth. Once a fortnight is plenty. Do it over a bowl, not an open drain.

What to avoid

• Chlorine: pools and cleaning products can pit white gold and platinum over time.
• Ultrasonic cleaners at home: fine for a solitaire, risky for pavé or anything with small stones.
• The gym, the garden, and the sea. Take it off. Prongs bend, and salt water is unkind to gold.

Storage

Separately. A diamond will scratch every other piece of jewellery it touches, including other diamonds. A soft pouch per piece, or the box it came in.

What we do

Bring it back once a year. We check the prongs, clean it properly, and re-polish the band. Resizing is complimentary. This is part of what you bought.

1. Decide the budget, then forget the rules

Ignore any formula involving months of salary; it was invented by a mining company's advertising agency in the 1930s. Spend what feels right. Because we grow the stone, that number goes further here than almost anywhere, and there is no shame in a beautiful one-carat.

2. Choose the shape first

Shape is the decision she will notice every day. Round if in doubt; oval or pear if she likes something longer; emerald or Asscher if her taste is clean and architectural. If you are guessing, look at the jewellery she already wears.

3. Set the cut to Excellent and leave it there

Everything else flexes. This doesn't.

4. Pick the carat that fits the hand and the setting

Ask to see a few sizes on a hand, or send us a photo of hers. A solitaire makes the stone look larger; a halo makes it look larger still; a thin band does the same.

5. Let colour and clarity find their level

Ask for eye-clean, not flawless. In white metal, G colour looks identical to D. That is where the budget goes back into carat.

6. Choose the metal

Platinum is heavier, whiter and wears slowly. White gold is lighter, a little warmer, and needs re-plating every few years. Yellow and rose gold flatter warmer skin and make a colourless stone look brighter by contrast. All of ours are solid, never plated over base metal.

7. Check the certificate number online

Before you pay. Every time. Two minutes.

8. Get the size right, or don't worry about it

Borrow a ring she wears on that finger and we'll measure it. If you can't, choose a 6 and we'll resize it for free after the question.

9. Ask what happens after

Warranty, resizing, cleaning, what if it doesn't suit. With us: lifetime on the craftsmanship, complimentary resizing and care, and returns if it isn't right. A seller who won't answer this question has told you something.