The Diamond Guide

An essential guide to selecting your diamond.

An expert breakdown of lab grown diamonds, the Four Cs, and grading certificates, written with absolute clarity by the people who cut and set these stones every day.

The one purchase most people make without an expert guide.

Most guides are built to sell. This one is built to educate. Understand precisely what alters a stone’s appearance, what drives its cost, and which details matter most when making your selection.

Chapter One

The true nature of lab grown diamonds.

A lab grown diamond is not a substitute or a simulant, it is a diamond in its purest physical form. Composed entirely of crystallised carbon, its physical, chemical, and optical properties are identical to mined diamonds. It shares the same brilliance, the same dispersion of light, and the same unmatched mineral hardness rating of 10 on the Mohs scale.

Even to an experienced jeweller using a traditional loupe or diamond tester, a lab grown diamond and a mined stone of identical specification appear completely identical. Only advanced spectroscopic analysis, reading microscopic trace signatures, can reveal their respective origins.

The fundamental difference is time and environment: where a mined stone crystallises beneath extreme subterranean pressure over millennia, a lab grown diamond develops over weeks in an environment that reproduces those exact physical forces.

Chapter Two

From seed to stone

Creation begins with a single diamond seed, a thin slice of existing diamond that serves as the structural blueprint for new carbon to build onto. From there, the growth environment does the rest.

Our standard method

Chemical Vapour Deposition

The seed sits in a sealed chamber heated above 700 °C. Carbon-rich gases, typically methane and hydrogen, are introduced and energised into a plasma. Carbon atoms separate from the gas and settle onto the seed one atomic layer at a time, growing the crystal upward.

CVD gives finer control over the growing conditions, which is why it accounts for most larger, high-clarity colourless stones, and why it is the method we use for the diamonds we sell.

Pressure: Low, near vacuum
Temperature: 700 to 1,200 °C
Typical growth: 3 to 6 weeks

High Pressure, High Temperature

The older of the two methods, mirroring the deep earth with pressure above one million pounds per square inch and temperatures beyond 1,400 °C. The finished stone is comparable, and we can source HPHT diamonds on request, though they carry a higher cost. If you would prefer one, please contact us.

Our atelier Every finished piece is checked by hand and, where certified, verified against its grading report before it leaves us.

After synthesis, the rough diamond is cut and finished by master artisans using the same tools and methods as mined rough. This transformation defines the stone’s ultimate aesthetic character and brilliance, explored in detail below.

Chapter Three

Understanding the Four Cs

Every certificate lists cut, colour, clarity, and carat. However, their contribution to a diamond’s actual appearance is vastly unequal. Below is a practical breakdown of how each factor shapes a stone’s beauty.

C

Cut

The most critical metric

Cut is distinct from stone shape; it denotes the accuracy of proportion, symmetry, and polish. It dictates how light behaves inside the diamond, returning maximum light through the top in radiant flashes, whereas poor proportions allow light to escape through the bottom.

Ideal Cut Light reflects internally and emerges through the table for optimal light return.

Too Shallow Light leaks through the bottom of the gem, causing a loss of brightness and depth.

Too Deep Light exits through the lower pavilion, darkening the centre and making the stone appear smaller than its actual weight.

What certificates do not show you

Laboratories do not assign cut grades to fancy shapes like ovals, pears, or marquises. Because these stones are graded only on symmetry and polish, a report will not detect a bow tie, a dark central band caused by sub-optimal cut angles.

This is why we inspect every fancy shape by eye before setting, giving you detailed video of your stone before you commit.

C

Colour

Graded D to Z

Diamond colour measures the presence or absence of visible tint. Running from D, entirely colourless, to Z, tinted yellow or brown, distinctions near the top of the scale are extremely refined. In practice, paying for the absolute top grade often yields a difference invisible once the stone is set.

D E F G H I J K L M N–R S–Z

Thanks to controlled growth conditions, lab diamonds consistently rank in the highest colour tiers. We supply D to E grades as standard. We avoid offering lower-grade stones to inflate headline discounts, keeping our pricing transparent, uncompromised, and direct.

C

Clarity

Flawless to included

Clarity evaluates the natural internal characteristics, known as inclusions, formed during crystallisation. A stone’s grade reflects the number, size, and position of these features under ten times magnification. In practice, the defining benchmark is whether a diamond is eye-clean, meaning no inclusions are visible to the unaided eye at a standard viewing distance.

FLFlawless IFInternally flawless VVS1Very very slight VVS2Very very slight VS1Very slight VS2Very slight SI1Slight SI2Slight I1–I3Included

While a Flawless rating offers ultimate theoretical purity, an Internally Flawless diamond and a carefully selected VS1 stone appear indistinguishable on the hand; the difference exists solely under a loupe. We curate VS1 clarity as our standard baseline, hand-inspecting every gem to ensure any minor inclusions remain completely imperceptible. We do not sell below VS1.

C

Carat

Measure of mass

A carat is a standard unit of weight equal to 0.2 grams. Crucially, carat measures mass rather than physical dimension, which is why two diamonds of identical carat weight can present vastly different surface areas when set. Excess mass concealed within a deep pavilion increases the number on a certificate without contributing any visual presence.

Select a weight below to compare the face-up diameter of a well-proportioned round brilliant.

1.00 ct

Diameter: 6.4 mm
Shape: Round brilliant
Our standard: D–E · VS1+

Select a weight to see it change.

We provide IGI certificates for lab grown diamonds of one carat and above.

The dimensions above represent a masterfully cut round brilliant. Elongated silhouettes, such as ovals, marquises, and emerald cuts, distribute their mass across a wider surface area. As a result, they occupy more space on the finger, delivering a visibly larger footprint than their carat weight implies.

Chapter Four

The two things worth spending on

To get the highest visual return on your budget, apply your investment strategically.

1

Cut, without compromise

A diamond’s sparkle and presence across a room are driven entirely by its cut. Never trade cut quality for raw weight or unseen colour grades. An excellent cut at 1.00 ct will consistently outshine a poorly proportioned cut at 1.50 ct.

2

Eye-clean clarity

Choose the lowest clarity grade that is verified eye-clean, then direct those savings into cut or carat size. In practice, no one examines a setting under ten times magnification.

Photographed, not rendered The fine jewelry featured in our imagery is handcrafted, never digitally rendered

Chapter Five

Certification, and how to verify it

A diamond certificate is an unbiased evaluation from an independent laboratory. It details the Four Cs, exact measurements, key proportions, a unique report number, and the growth method. Without third-party certification, a grade is just an unverified claim.

Our standard

Lab grown diamonds of one carat and above are IGI certified, included in the price.

The International Gemological Institute grades the vast majority of lab grown diamonds worldwide and provides the industry’s most trusted reports. Certification comes standard with stones of one carat and above, never as an upcharge, because buying a fine diamond should never rely on blind faith.

Your report number is listed on your product page and included in your paperwork, and many stones also carry it laser-inscribed on the girdle for easy viewing under magnification.

Verify it independently

Find your report numberLocated on your product listing, your paperwork, or the girdle inscription.
Head to the lab websiteNot ours. Access the independent registry at igi.org.
Input the report numberPull up the official report directly from the lab.
Cross-check the detailsVerify that every metric aligns perfectly with your purchase details.

A loose diamond held in tweezers above a stone case, with laboratory certificates alongside

Stones below one carat

Smaller diamonds are not certified as standard. The cost and the laboratory turnaround are disproportionate to the stone, and every piece is graded to the same D–E, VS1 and above specification whether or not it carries a report. If you would like a certificate for a smaller stone, ask us and we will quote for it.

In the showroom: every certified stone is checked against its report before it leaves us.

A tray of coloured gemstone rings set with pink diamonds and emeralds

Coloured gemstones

Emeralds, sapphires, rubies and fancy coloured diamonds are certified on request rather than as standard. Coloured stone reports are considerably more expensive and take around four weeks, so we arrange them individually rather than build the cost into every piece.

On request: coloured stone certification is arranged individually.

Chapter Six

Lab grown or mined

The honest comparison, including the part most retailers leave out.

Like for like, at matched specification
	Lab grown	Mined
Chemical composition	Pure crystallised carbon	Pure crystallised carbon
Hardness	10 on the Mohs scale	10 on the Mohs scale
Brilliance and fire	Identical	Identical
Visible difference	None. Separation requires specialist laboratory equipment.
Typical price, like for like	Substantially less	The benchmark
What that buys you	A larger stone, a better cut, or a higher colour grade for the same outlay	Rarity, and the value the market places on it
Traceability	Origin known and documented	Varies by supply chain
Environmental footprint	Energy used in growth, no extraction	Significant earth moved per carat

Chapter Seven

Choosing a shape

Shape is the most personal decision in the process and the one least worth over-thinking. Each behaves differently with light and sits differently on a hand.

Ten loose lab grown diamonds in a stone case, one of each cut — Photographed, not rendered Every cut below is one of our own stones, photographed in the showroom.

Round

The most brilliant. The only shape with a formal cut grade.

Oval

Elongates the finger and looks larger than its weight.

Emerald

An elegant, rectangular shape with long, parallel facets. Utilises step-cut faceting to create a “hall-of-mirrors” effect.

Pear

A teardrop. Directional, and flattering worn point-up.

Cushion

Softened corners, a warmer and more antique character.

Marquise

The largest apparent size per carat. Prone to a bow tie if cut poorly.

Radiant

The outline of an emerald cut with the fire of a brilliant.

Princess

A brilliant cut in a square outline. Sharp and contemporary.

Asscher

A square step cut. Architectural, with a deep hall-of-mirrors effect.

Heart

The most demanding to cut well. Symmetry is everything.

Chapter Eight

Determining the ideal fit

Selecting the correct size discreetly requires subtle consideration, and it is the question we are asked most often. Sizing systems differ by country: the United Kingdom uses letters, the United States uses numbers, and much of Europe uses the inside circumference in millimetres. The most common women’s sizes fall between UK J and N, or US 5 to 7.

When planning a surprise commission, three reliable methods preserve the secret:

Discreetly borrow a ring worn on the intended finger for atelier measurement.
Seek counsel from a confidant who holds discretion in high regard.
Favour a slightly generous size, as taking a ring down is far more straightforward than expanding it.

International size chart

Find the row that matches the ring you already have, then read across to your own country's system. If you can measure the inside of an existing ring, that measurement is the one to give us; letters and numbers vary very slightly between jewellers, but millimetres do not.

Women's sizes, UK H to UK T½
Inside diameter	Inside circumference	UK & Australia	US & Canada	Europe	Japan & China	Hong Kong
14.9	46.8	H	4	47	7	10
15.3	48.0	I½	4½	48	8	10½
15.7	49.3	J½	5	49	9	11½
16.1	50.6	K½	5½	51	11	12½
16.5	52.0	L½	6	52	12	13½
16.9	53.1	M½	6½	53	13	14
17.3	54.4	N	7	54	14	15
17.7	55.7	O½	7½	56	15	15½
18.1	57.0	P	8	57	17	16½
18.5	58.3	Q	8½	58	18	17
18.9	59.5	R½	9	60	20	18
19.4	60.8	S½	9½	61	21	18½
19.8	62.1	T½	10	62	22	19½

Measurements are in millimetres. European sizing is the inside circumference rounded to the nearest whole number. Japanese and Chinese sizes follow the same scale as one another. If your size falls between two rows, take the larger, particularly for a wide band.

Contact us for resizing

For made to order items, we can arrange a resize within the first year.

Questions

The things people ask us

Can a jeweller tell if a diamond is lab grown?

No. A jeweller cannot tell by eye, under a loupe, or using a standard diamond tester, which reads the stone as a real diamond because, chemically, it is. Differentiating the two requires specialised spectroscopic equipment used in gemological laboratories. Your certificate clearly discloses the stone’s origin as part of our commitment to full transparency.

Do lab grown diamonds cloud or dull over time?

No. This is a common myth. A diamond's optical properties never change. If a ring starts to look dull, it is simply due to a build-up of everyday skin oils and soaps behind the stone. Cleaning it with warm water, mild dish soap, and a soft brush will restore its original sparkle in minutes.

Are lab grown diamonds cheaper because they are lower quality?

No. They cost less because they are not constrained by natural scarcity, which accounts for most of a mined diamond's price tag. At equal specifications, the two are optically identical. The price difference simply allows you to choose a larger stone, a higher cut grade, or a better color grade for your budget.

Can I trade up to a larger stone later?

Yes. If you buy a diamond from us and later decide you would like a larger one, talk to us and we will set out exactly what it would cost.

Can I see the actual stone before I commit?

Yes, and we would encourage it on any significant purchase. Ask for a consultation and we will film the stone for you in our showroom, under proper lighting and alongside its certificate, so you can watch it, share it, and ask us whatever you want. A short video call can be arranged as well if you would rather talk it through. Details are on our consultation page.

How long will my piece take to arrive?

Ready to ship pieces are dispatched within 2 business days. Made to order pieces are made in 12 to 15 days once your design is approved. Delivery then takes 3 to 7 business days, fully insured and tracked.

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