Choosing a lab-grown diamond becomes far simpler once you write a short brief for yourself first. A brief is just five decisions, shape, carat, colour, clarity and the figure you want to spend, settled before you start comparing stones, so that what you see online matches what you actually want.
This guide walks through each decision in the order most Australian buyers find useful. By the end you will have a one-line summary you can bring to any jeweller, including us, and know exactly what you are asking for. Nothing here requires prior knowledge, and you can complete the whole brief in about ten minutes.
Why write a brief at all
A lab-grown diamond is chemically, physically and optically identical to a mined diamond. The difference is origin and value, which means the same money goes considerably further. That advantage only helps you if you know what you are looking for, otherwise it is easy to overspend on a quality you cannot see, or to compromise on the one feature that actually matters to you.
Buying a diamond can feel like learning a new vocabulary under pressure. A brief removes that pressure. Instead of reacting to whatever a search result happens to show, you arrive with a clear specification and measure each stone against it. The result is a calmer process and, almost always, a better-matched diamond for the money.
The four traditional grading factors, cut, colour, clarity and carat, are often called the 4Cs. We add a fifth practical factor for real buyers: the amount you plan to spend. Setting all five in advance turns an open-ended search into a short, confident shortlist. You can read our fuller explanation of the grading factors on our guide to the 4Cs.
Decision one: shape
Shape is the most personal and the most visible decision, so it belongs first. It also influences everything that follows, because some shapes show colour and clarity differently to others, and a few present larger than their carat weight.
The round brilliant is the most popular cut in Australia. Its faceting is engineered for maximum brilliance and fire, and it hides faint colour and minor inclusions well, which is why it remains the default for engagement rings. If you want the most light return for the carat, start here.
The main alternatives fall into two groups:
- Brilliant-style fancy shapes such as oval, pear, cushion, marquise and heart. These share the round's sparkle but offer a different outline. Oval and pear also look larger than their carat weight because the shape spreads the stone across the finger.
- Step cuts such as emerald and Asscher. These trade fire for clean, architectural lines and a hall-of-mirrors clarity. Because the facets are long and open, they show inclusions and colour more readily, so they reward a slightly higher clarity and colour grade.
If you are undecided, consider the wearer's hand, the setting style they like and whether they prefer obvious sparkle or quiet geometry. Slim or longer fingers tend to suit elongated shapes such as oval and marquise; rounder hands often carry a round or cushion well. There is no wrong answer here, only the one the wearer will be happiest seeing every day. You can compare every shape side by side in our full diamond collection.
Decision two: carat
Carat is weight, not size, though the two are related. A 1ct round diamond measures roughly 6.5mm across; a 2ct round is about 8.1mm. Weight doubles, but the visible diameter grows by only around a quarter, so the jump from one to two carats looks smaller on the finger than the number suggests.
Two practical points help here. First, certain weights, particularly the round numbers like 1.0ct and 2.0ct, attract a small price step because they are in high demand. A 0.9ct stone can look almost identical to a 1.0ct stone for noticeably less. Second, elongated shapes such as oval, pear and marquise present more surface area per carat, so they read as larger than a round of the same weight.
It also helps to think about the setting before you fix a weight. A halo of smaller stones around the centre diamond makes the whole piece appear larger, which can let a slightly smaller centre stone do the same visual work for less. A solitaire, by contrast, puts every carat on show.
Decide on a carat range rather than a single figure. A brief that says "1.4ct to 1.6ct" gives you a workable shortlist; "exactly 1.5ct" narrows it unnecessarily and can rule out a better-matched stone for the sake of a number.
Decision three: colour
Diamond colour is graded from D, which is colourless, down through the alphabet as a faint warmth appears. For most buyers the visible difference between adjacent grades is slight, and the right grade depends on your shape and your setting.
- D to F (colourless): the highest grades, worth prioritising for step cuts and for platinum or white gold settings where any warmth would show.
- G to H (near colourless): the practical choice for most buyers. The stone faces up white to the eye, especially in brilliant-style shapes, with no need to pay for grades you cannot see.
- I to J: a faint warmth that can sit beautifully in yellow or rose gold, which masks it, and stretches your spend further across the other factors.
A useful rule: match the colour grade to the metal. A near-colourless stone in white metal asks for a slightly higher grade than the same stone set in yellow gold, where a warmer tone reads as intentional rather than as a flaw.
If you would prefer deliberate colour rather than the absence of it, that is a separate path. Yellow, pink, blue and other fancy colours are graded on saturation rather than the D to Z scale, and they make a distinctive choice for a buyer who wants something out of the ordinary.
Decision four: clarity
Clarity describes the tiny natural inclusions formed as the diamond grows. The scale runs from Flawless (FL) through Internally Flawless (IF), Very Very Slightly Included (VVS1, VVS2), Very Slightly Included (VS1, VS2) and below.
The phrase to know is "eye-clean": a diamond whose inclusions cannot be seen by the unaided eye at a normal viewing distance. For most shapes, a VS1 or VS2 stone is reliably eye-clean, which is why we set VS1 as our minimum and never sell below it. Paying for IF or FL buys certainty under magnification, not a difference you will see while wearing the ring.
Where an inclusion sits matters as much as the grade. A small inclusion near the edge of the stone, where a setting prong can cover it, affects the look far less than one sitting directly under the table at the centre. A good supplier will tell you where the inclusions fall and why a particular stone still reads as eye-clean.
Step cuts are the exception to the relaxed approach. Because emerald and Asscher cuts have those long, open facets, inclusions are easier to spot, so a slightly higher clarity grade is worth the spend if you have chosen one of those shapes.
Decision five: what you plan to spend
Set your figure last, once you know what you value, so the number serves your priorities rather than dictating them. As a reference point, a 1ct round lab-grown diamond at CRTD starts from around $990 AUD, certified and ready to set. You can see how price moves with the four grading factors on our 1 carat lab-grown diamond page.
When you are balancing the factors against a fixed figure, a sensible order of priority for most buyers is:
- Cut first. Cut quality drives brilliance more than any other factor. A well-cut stone outperforms a larger, poorly cut one, so this is the place not to compromise.
- Carat and colour next, traded against each other. Dropping from a colourless to a near-colourless grade often funds a meaningful step up in size with no visible loss.
- Clarity last, held at an eye-clean grade. There is rarely a reason to pay beyond VS1 unless you have chosen a step cut.
Remember to leave room in your figure for the setting and for insured delivery, so the amount you allocate to the diamond is not the whole of what you spend. A loose stone is only part of the finished piece, and the setting can add meaningfully to the total depending on the metal and design you choose.
Putting your brief together
With the five decisions made, write them as a single line. A complete brief might read: "Oval, 1.4ct to 1.6ct, G to H colour, VS1 clarity, around $2,000 for the loose stone." That sentence tells any jeweller exactly what to source, and it protects you from being talked into qualities you decided you did not need.
Keep the brief as a range wherever you can. Ranges give a supplier room to find the best-matched stone rather than the nearest exact match, and lab-grown diamonds are sourced individually, so two stones at the same grades can still differ in price and character. A small amount of flexibility usually returns a better diamond.
Every CRTD diamond is independently certified by IGI, GIA or an equivalent laboratory, sourced to order against your brief, inspected before dispatch and sent by insured courier from our Sydney base. Because we source rather than hold stock, your brief is the starting point: the tighter it is, the better the match. You can read more about that process on our how we source page.
Frequently asked questions
How do I choose a lab-grown diamond in Australia?
Decide five things before you compare stones: shape, carat range, colour grade, clarity grade and the figure you want to spend. Choose shape first because it is the most personal and affects how colour and clarity show. Then prioritise cut quality, balance carat against colour, and hold clarity at an eye-clean grade such as VS1. Bring that one-line brief to a certified Australian supplier who can source to your specification.
What is the best colour and clarity for the money?
For most buyers, a G or H colour paired with a VS1 or VS2 clarity gives a diamond that faces up white and is eye-clean, with no spend on differences only visible under magnification. Step cuts such as emerald and Asscher are the exception and reward a slightly higher colour and clarity grade because their open facets reveal more.
How much is a 1 carat lab-grown diamond in Australia?
At CRTD, a 1ct round lab-grown diamond starts from around $990 AUD, certified and ready to set. The exact figure depends on the colour, clarity and cut you choose, and on the shape. Elongated shapes and round numbers like a precise 1.0ct can carry a small price step relative to a 0.9ct stone that looks almost identical.
Is a lab-grown diamond a real diamond?
Yes. A lab-grown diamond is chemically, physically and optically identical to a mined diamond. It is graded on the same factors, certified by the same independent laboratories such as IGI and GIA, and the only practical differences are its origin and its value, which lets the same money buy a larger or higher-graded stone.
Bring us your brief
Once you have your five decisions written down, the hard part is done. Explore our full collection to settle on a shape, then contact us with your brief and we will source a certified stone to match, inspect it, and deliver it insured from Sydney.