Diamond & Gold — Melbourne's Fine Jewellery House
The certificate says "lab diamond." So does the other one. So why does one blaze across a room while the other sits quietly on the finger, noticed by no one? A twenty-year Melbourne perspective on the questions most retailers would rather you didn't ask.
The democratisation of the lab diamond has been, on balance, a wonderful thing. Stones of real size, real beauty and real certification are now available at price points that would have been implausible a decade ago. But democratisation always carries a shadow: when supply expands rapidly, so does the range of quality within it. Not every lab diamond sold with a grading report and a confident marketing description is a stone that will make the person wearing it catch their breath — and in Melbourne's fine jewellery studios, the difference is visible from across the room.
At D and G company, we spend a significant portion of our working lives sorting good lab diamonds from truly exceptional ones. This article is our attempt to share exactly what that sorting process looks like — the technical reality beneath the sales language, laid out plainly for the buyer who wants to understand rather than simply trust.
The core truth: Lab diamond quality differences are real, measurable and visible. Two stones with matching certificates can look dramatically different in person. The factors that separate a stunning lab stone from a mediocre one are largely the same as they are for mined diamonds — with one additional layer of complexity unique to how lab diamonds are grown. Knowing that layer is what gives a knowledgeable Melbourne buyer a genuine edge.
First: Dispense with the "Lab Diamond Is Lab Diamond" Myth
It is common, particularly in online communities, to hear that once a lab diamond is certified, quality becomes purely a matter of the four Cs — that the process of growing it in a reactor rather than extracting it from the earth removes all other variables. This is not quite true, and believing it is the most expensive mistake a careful buyer can make.
Certification establishes a minimum floor: the stone has been examined, graded, and found to meet certain specifications. What certification does not capture — and what the most experienced eye in a Melbourne showroom can tell you in under thirty seconds — is how a stone actually behaves with light. That behaviour is governed by variables that sit both within and beyond what a grading report records.
The Factor That Matters More Than Any Other: Cut
If there is one truth in diamond retail that we repeat to every single client regardless of budget or background, it is this: cut is not one of the four Cs. Cut is the only C that actually matters to the eye. Colour and clarity both describe what a diamond has or lacks. Cut describes what a diamond does — specifically, how efficiently it collects, redirects and returns light to the viewer.
A poorly cut lab diamond with a flawless clarity grade and the whitest colour tier will look flat, glassy and inert. An excellently cut lab diamond with a more modest colour and clarity grade will blaze. This is not opinion; it is optics. Light entering a well-proportioned stone exits through the table in concentrated, brilliant flashes. Light entering a poorly proportioned stone leaks out through the pavilion, and the result is a diamond that looks dull under most of the lighting conditions a person actually lives in.
What to Look For
The Cut Grade That Actually Means Something
For round brilliant lab diamonds, insist on Excellent or Ideal cut grades from an independent laboratory — IGI or GIA. But go one step further and check the sub-grades: table percentage (ideally 53–58%), depth percentage (ideally 59–62.5%), and crown and pavilion angles. A stone graded Excellent overall can still carry proportions that compromise its performance if the sub-grades sit at the outer edges of the range. Your eye catches this before your intellect does — which is precisely why seeing the stone in person, under real Melbourne daylight, is irreplaceable.
What to Avoid
The "Very Good" Grade That Is Doing Heavy Lifting
In cut grading, "Very Good" sounds like a near-miss from the top. In practice, the Very Good range accommodates a wide spectrum, and the bottom end of it produces stones that underperform significantly compared to a genuine Excellent. If budget pressure forces a step down from Excellent, ask your Melbourne jeweller to show you both side by side before deciding — the gap is often visible, sometimes dramatically so.
Frequently Asked
Does cut grading work the same way for fancy shapes as it does for round brilliants?
No — and this is a genuine complication that the industry has not fully resolved. Round brilliants benefit from decades of optical modelling and standardised cut grading by the major laboratories. Fancy shapes — ovals, cushions, pears, emeralds — are not subject to the same standardised system, which means a grading report for an oval lab diamond tells you far less about its light performance than one for a round. For fancy shapes, there is currently no substitute for seeing the stone in person: assessing the degree of bow-tie effect in an oval, the brightness distribution in a cushion, the windowing in a pear. An experienced Melbourne jeweller who has physically sorted hundreds of fancy-shape lab diamonds is worth considerably more than any certificate when it comes to these selections — it is one of the reasons we consider this part of our work genuinely specialist, not simply retail.
The Lab-Specific Variable: Growth Method and Its Consequences
Here is the layer of complexity that is unique to lab diamonds, and the one that receives the least plain-language explanation in most retail environments. Lab diamonds are currently grown by two distinct processes — HPHT (High Pressure High Temperature) and CVD (Chemical Vapour Deposition) — and the method of growth affects the stone's optical character in ways that matter to a careful eye.
Growth Method One
HPHT: The Original Process
HPHT mimics the geological conditions under which mined diamonds form — extreme pressure and temperature applied to a carbon source. Stones grown this way tend to have cubic crystal structure and often exhibit strong, directional fluorescence. At their best, HPHT stones are extraordinarily white and exceptionally transparent. At their worst, they can show strain patterns and graining that affect optical clarity in ways a standard grading report may not fully capture. Colour in HPHT stones is generally excellent — the process is particularly good at producing D–F colour grades — but the gem trade watches HPHT stones carefully for a specific optical artefact called "synthetic graining," visible under magnification, which has no mined equivalent.
Growth Method Two
CVD: The Dominant Modern Process
CVD grows diamonds layer by layer from a carbon-rich gas, producing a crystal structure that is often described as more "regular" than HPHT. The majority of lab diamonds sold today, including most of the stones we work with in our Melbourne studio, are CVD-grown. CVD stones can be outstanding — but the process introduces its own characteristic issue: a brown or grey tint that can develop during growth and is frequently treated post-growth with HPHT processing to remove it. This treatment is entirely standard and legitimate, but it underscores the point that a colour grade on a CVD stone's report is the grade after treatment, not the grade of the rough. The key question to ask about any CVD stone is whether post-growth treatment has been performed and disclosed — at our Melbourne studio, we consider disclosure non-negotiable at any price point.
"The best lab diamond is not the one with the most impressive certificate. It is the one that, when you hold it to the light, makes everything else in the room disappear."
Colour: What the Grades Don't Tell You About Warmth
Colour grading in diamonds runs from D (perfectly colourless) to Z (noticeably tinted). For the purposes of a lab diamond engagement ring worn on a human hand, in real-world lighting, the practical range is D through J — and within that range, lab diamond quality differences in colour are often less perceptible than the grading system implies, but more nuanced than the marketing suggests.
Here is what the grade does not tell you: how the stone's colour reads in the setting it will actually live in. A D colour lab diamond in a yellow gold solitaire will appear warmer than the certificate suggests because the setting reflects colour into the stone. An H colour in platinum, well cut, will face up whiter than many buyers expect. The relationship between stone colour, setting metal, and ambient light is one of the things our Melbourne designers discuss in depth when clients explore engagement ring styles — because the combination matters as much as the stone specification in isolation.
Frequently Asked
Is a D colour lab diamond always the best choice?
Rarely, in our experience — and we say that as people who handle D colour stones regularly. D through F colour grades are indistinguishable to the naked eye once the ring is on a hand, and the premium for D in a lab diamond is meaningful without being justified by any visible benefit over, say, an F or G. The premium exists because D is the top of the scale, not because the human eye at arm's length can perceive the difference. Where the colour grade genuinely matters is at the J and K boundary in larger stones — above roughly 1.5 carats, warmth becomes perceptible to most eyes without needing to look carefully. Below that threshold, a well-cut G or H colour in a good setting will satisfy even the most demanding eye, and the budget saved is better spent on cut quality or carat weight. This is the honest advice we give every Melbourne client regardless of which direction it moves the sale.
Clarity: Eye-Clean Is the Standard That Actually Matters
Clarity in a lab diamond describes the presence or absence of internal characteristics — growth features, pinpoints, graining — that form during the growing process. The grading scale runs from Flawless to I3, and the most important concept for a practical buyer to understand is "eye-clean": free of inclusions visible to the unaided eye at arm's length, in normal lighting conditions.
The practical implication is significant. A VS2 or SI1 lab diamond that is eye-clean performs identically, in every way that a person wearing it can perceive, to a Flawless stone. The inclusions that separate them exist under ten-times magnification — in a grader's loupe, not in the room where the ring is worn. Paying for Flawless clarity in a lab diamond is a choice, not a necessity; it buys the knowledge that the certificate says Flawless, not anything the eye can see. We find this knowledge satisfying for some clients and irrelevant to others, and we discuss it plainly so the decision is genuinely informed.
What clarity genuinely affects — and what a grading report alone cannot protect you from — is the nature and position of inclusions. A central, dark inclusion that sits directly under the table of the stone is far more distracting than a feather near the girdle, even if both earn the same grade. This is another reason that seeing the actual stone, in our Melbourne studio, is the step that makes the paperwork meaningful rather than simply theoretical.
Fluorescence: The Most Misunderstood Quality Factor
Fluorescence — the tendency of some diamonds to emit a blue glow under ultraviolet light — is listed on grading reports and treated with either irrational fear or indifference by most buyers. The reality is more interesting than either reaction.
In mined diamonds, strong blue fluorescence occasionally makes a lower-colour stone appear whiter in sunlight (which contains UV), which can be a subtle advantage. In lab diamonds, fluorescence patterns are somewhat different from mined stones — CVD-grown diamonds can show a characteristic orange or orange-pink fluorescence that is specific to the growth process, and HPHT stones sometimes show strong directional blue or green fluorescence. Neither is cause for alarm, but both are worth knowing about and asking about, because strong or unusual fluorescence in certain lighting conditions can affect how a stone reads to the eye. In the trade, we treat atypical fluorescence as a characteristic to be aware of and disclosed — not a defect, but also not something to be glossed over in a purchase conversation.
The Setting as Quality Amplifier — or Diminisher
A mediocre stone in an extraordinary setting reads as a beautiful ring. An extraordinary stone in a mediocre setting reads as a disappointment. This is a principle we apply rigorously in our Melbourne workshop, and it informs everything from the claw height we specify (too low and light entry is compromised; too high and the profile looks awkward) to the metal thickness under the gallery (too heavy and the setting interferes with light passage; too delicate and structural integrity becomes a long-term concern).
The reason this matters for a quality conversation is that the setting is a quality decision as much as the stone is — and it is one that an online purchase frequently takes out of your hands. When you build own engagement ring designs in our Melbourne studio, the setting is crafted around the specific stone selected, not adapted from a generic mount designed for a range of sizes. That distinction is visible in the finished ring, particularly at larger carat weights where the relationship between stone geometry and setting architecture becomes more complex.
| Quality Factor | What the Certificate Shows | What Only Your Eyes Can Judge |
|---|---|---|
| Cut | Grade (Excellent / Very Good etc.); sub-grades | Actual light return, scintillation pattern, face-up brightness |
| Colour | Letter grade (D–Z) | How the stone reads in its actual setting and metal |
| Clarity | Grade; inclusion map | Whether inclusions are visible at arm's length; their position and distraction |
| Fluorescence | Strength and colour noted | How it affects the stone's appearance in sunlight vs. indoor light |
| Growth method | Sometimes noted; often not | Optical character, graining, post-growth treatment disclosure |
| Setting quality | Not measured at all | Light passage, structural elegance, metal finish, long-term wearability |
What This Means for the Practical Melbourne Buyer
The research-heavy buyer — the one reading articles like this one, comparing certificates across multiple retailers, building spreadsheets — has every instinct right. The information genuinely matters. What the spreadsheet cannot do is turn a grading report into the experience of watching a particular stone catch the light above a coffee on Collins Street and deciding, without any further analysis, that it is the one.
The certificate is the shortlist. Your eyes are the decision.
This is why we encourage every Melbourne client to visit our studio before committing, regardless of what the online research has already established. Our collection of economical engagement rings is sourced and set to the same standard as our most significant commissions — because we apply identical sorting discipline regardless of price point. A well-cut, eye-clean lab diamond in an honestly crafted setting at a considered price is a better ring than a higher-graded stone carelessly set and sold from a photograph. That distinction is what twenty years in Melbourne's jewellery trade has taught us to make — and it is the distinction we apply on behalf of every client who walks through our door.
And when the engagement ring conversation leads, as it usually does, to wedding bands — our gents wedding rings are sourced and crafted with the same rigour, because the standard should not change simply because the ring is worn by a man or carries a lower price expectation. Every ring we make in Melbourne is made the same way: with the same certified stones, the same in-house craftsmen, and the same honest conversation about what the numbers mean and what the eye actually sees.
A note for the long view: rings grow with the people who wear them. Fingers change, settings require maintenance, and — more often than expected — a band that fitted perfectly at twenty-eight needs gentle adjustment at thirty-eight. Our published ring resizing cost reflects in-house work by the same craftsmen who made the ring, not an outsourced process — which is another reason that buying locally, from a Melbourne workshop with a physical address you can return to, pays dividends that a purchase price alone cannot capture.
Frequently Asked
How do I know if a Melbourne jeweller is actually selecting quality lab diamonds, or simply passing on whatever the supplier sends?
Ask directly — and pay close attention to how the question is received. A jeweller who sources and sorts stones with genuine discipline will be able to tell you what they reject and why: the proportion ranges they won't accept regardless of grade, the fluorescence characteristics that give them pause, the way they assess eye-cleanliness before recommending a clarity grade to a client. If the response is a marketing description of the laboratory that certified the stones, that tells you something. In our Melbourne studio, we can walk you through the stones we chose not to stock this month alongside the ones we did — because the comparison is the most direct demonstration of what "quality selection" actually means in practice, rather than in a brochure. The ability to explain rejection criteria is, in our view, the clearest signal of genuine expertise in this area.
The Standard We Hold Ourselves To
We are not the largest jeweller in Melbourne. We are not the loudest, and we are not the cheapest — though we work hard to ensure that the difference between our pricing and a discount retailer's is explained entirely by what you can see and touch, not by margin hidden in a brand name. What we are is specific: specific about cut sub-grades, specific about growth method disclosure, specific about fluorescence characteristics, specific about the setting craftsmanship that determines how a stone performs over a lifetime of wear rather than simply on a display pad under a spotlight.
The difference between a stunning lab diamond and a mediocre one is real, visible and — once you know how to look — immediately apparent. We would like to show you that difference in person. Bring us the certificates you've been comparing. Bring us the questions the spreadsheet raised but couldn't answer. Bring the scepticism; it is entirely appropriate, and we would rather earn your confidence than assume it.