A gemologist’s guide to buying a natural diamond
Shopping for a natural diamond – especially for something as important as an engagement ring – should feel exciting. If you’re starting your search in Montreal or Canada (we also ship globally), we’re here to make sure it feels exciting, not overwhelming.
As a gemologist and designer at LOFT.bijoux, I’ve helped many clients find their perfect diamond. And here’s the truth: there is no “perfect” diamond. But there is one that’s perfect for you.
You are probably doing now what most of my clients are doing: reading everything you can find online. From my conversations with so many people, I see that this path is sometimes a bit misleading. Many of the articles focus on clarity grades (VS, SI, etc.) and colour scales (D-E-F, etc.), and while those factors matter, they are not the most important thing.
Start Here: How to Choose a Diamond
As a gemmologist and designer, I can tell you: the most important characteristic of a diamond is the Cut. And the fifth C, the Character.
But let’s start with the basics, the famous 4Cs: Cut, Clarity, Color, and Carat. (The big houses of high jewelry, for example Van Cleef & Arpels, also add the fifth C – Character).
1.
Cut — My Personal #1
If there’s one thing I always look at first, it’s the Cut. Why? Because diamonds are little optical devices, and cuts are calculated mathematically to reflect all the light entering from the surface. That’s what gives it sparkle — that real, breathtaking brilliance — no matter the shape.
A poorly cut diamond, even with great color and clarity, will always look a bit… meh. But a well-cut stone? Magic.
At LOFT.bijoux we normally stay at Excellent and Very Good cuts, unless you fall in love with another diamond for a different reason (seen it happening multiple times, because sparkle is not always the goal).
If we go deeper into diamond cut, there are a few critical details that are often overlooked – like proportions and girdle thickness. I won’t go too deep into this professional material (ask me if you want to know more!), will just add that if the girdle (the thin band around the diamond) is too thin, it can create fragilities and affect the brilliance. Proportions also have a huge impact, particularly you see it in the fancy shapes (everything except rounds).
2.
Clarity
Clarity is about how many inclusions (internal marks) or blemishes a diamond has — and where they are. But clarity grades can be misleading without context.
For example, an SI1 diamond (Slightly Included) can be completely EyeClean — meaning, to the naked eye, it looks flawless. Or… it can have a black spot right in the center that you see instantly.
Why the difference? Because not all inclusions are equal. A tiny feather on the side hidden under the sparkly facet can be almost invisible, while a black spot in the center stands out. That’s why we always show you actual diamonds so you can compare. Two stones with the same grade can look completely different.
3.
Color
Diamonds are graded from D (colorless) to Z (noticeably yellow). The bigger the stone the harder (or much more expensive) is to get the D-E colours, but the good news, unless you put two diamonds together on the white tray, you might not see the difference between colorless grades (D-E-F) and nearly colorless (G-H-I-J). I’d say, the untrained eye starts normally seeing slight yellow hint at I-J and lower.
That’s why we love showing you options in person (or over video!) — so you can see what feels right to you, not just what the grading report says.
4.
Carat
Carat is weight, not size. While there are standard ranges for sizes for different weights, stones can measure very differently for the same weight. Particularly, the fancy cuts (everything except rounds).
And as carat weight increases, so does the price — but also the impact of small differences in clarity and color.
That’s why we always say: the bigger the diamond, the more it makes sense to compare a few options. Is that small bump in clarity really worth $3,000 more? Sometimes yes, sometimes no. It depends on the stone — and your eye.
You might sometimes hear that a diamond “weighs 1 carat but faces up like a 1.1 carat”, for example. It means that the surface dimensions (the visible face of the diamond) are larger than usual for that weight – which also means the diamond is cut thinner.
Now, in some cases, a diamond that faces up slightly bigger can be a smart choice. But more often, a thin stone sacrifices brilliance. It may look large but lack life – creating “windows” – areas that are dark or without sparkle.
Understanding Diamond Certificates (GIA and Others)
Not every diamond comes with a lab certificate – and that doesn’t necessarily mean it’s a bad stone. But let’s talk about what certificates are and why they matter.
There are several major gemological labs that issue diamond grading reports. The most famous in North America is GIA – The Gemological Institute of America. But there are also IGI, HRD, and a few others, all totally legitimate for insurance and valuation purposes.
Every time a diamond is sent to the lab, there’s a cost involved - $100-$150 for the report itself, plus insured shipping to and from the lab. For example, if we want to send a diamond from Montreal to GIA New York, the added cost will exceed $300. It is not always wanted by the clients if they have a smaller diamond. Sometimes diamonds are passing by the lab in a big lot and still get reports even in smaller sizes, because the cost is optimized, but it’s not always the case. That’s why diamonds of 0.3-0.4ct would not necessarily have a certificate. Usually, my diamonds of 0.5ct and more will have a certificate.
If there is none, and you would still like to have it – I recommend Montreal Institute of Gemology, it has a fully equipped lab, it will cost you around $100 and will be a fully functional report for your insurance company.
An important thing you need to understand – the lab report doesn’t give the value of your diamond. (For that you need a gemologist’s evaluation certificate).
The report includes:
· Cut, color, clarity, and carat weight
· Polish and symmetry
· Fluorescence (sometimes important)
· Inclusion map (useful for SI and VS stones)
· A laser inscription you can match to the diamond
BEYOND CERTIFICATES
I can talk for long about each diamond, and that’s what is usually happening during our consultations with clients. I like to show a selection of stones to illustrate different characteristics. But I still would like you to benefit a little bit from part of my consultation via this blog and want to give you some tips relevant to different shapes of diamonds.
Cut-Specific Tips (Because Shape Changes Everything)
Each shape has its own strengths — and quirks. Here’s what to keep in mind when choosing:
Emerald Cuts
Elegant and clean — but also transparent.
Emerald cut is the most “clarity-unforgiving” shape. Clarity matters. Go for VS2 or better. The large open table and step cut reveals everything. Inclusions that would be invisible in a brilliant cut under the facets will stand out here.
Ovals & Marquises
Romantic, flattering shapes — but tricky.
Proportions are everything. Poor cuts often have a “bowtie” effect — a dark zone across the middle with no sparkle. We always handpick diamonds to avoid this.
Marquise, oval, pear are the shapes that will look larger for their weight than, for example, a round, because according to their proportions they need to be cut thinner (particularly, the marquise).
Round Brilliants
Classic for a reason — maximum fire and sparkle.
Cut is king. You can go down to SI1 clarity if the stone is EyeClean. Prioritize excellent cut first, it can compensate for many of the inclusions and lower colour grade.
Cushion Cuts
Soft, vintage, and full of personality.
Be careful with depth and shape — too much depth can make the stone look smaller. Always check brilliance in motion. Now there is a fashion for more elongated shapes, but be attentive when the cushion is too long – I can create a bow-tie just like in an oval.
Pear Cuts
Unique and bold.
Symmetry matters a lot here. A misaligned tip or off-center culet can throw the look off completely. And yes — pears can also get bowties if not well-cut.
What Natural Diamonds Cost
Pricing varies depending on market, color, clarity, and availability. But to give you a ballpark for GIA-certified, well-cut natural diamonds in Canadian dollars (as of mid-2025):
· 0.30 ct: from $800 to $1,500
· 0.50 ct: from $1,800 to $3,500
· 0.70 ct: from $4000 to $7,000
· 1.00 ct: from $6,000 to $10,000+
· 1.50 ct: from $12,000 to $18,000+
· 2.00 ct: from $22,000 to $35,000+
Again — two diamonds at the same carat weight (and even sometimes of the same clarity, cut, etc.) can have completely different prices because the actual look of the diamond can be completely different even with the same characteristics.
That’s why we always show you several options, so you can compare and decide what feels worth it.
Tips from Our Atelier
· Always look at the diamond in natural light, not just store lighting (particularly in case of fluorescence – sometimes it will have a zero impact on the stone, sometimes may change it dramatically)
· Look beyond the grade — see the actual diamond
· Prioritize cut — it brings the magic
Ask questions — we’re here for that
Ready to Choose Your Diamond?
We’d love to help. Whether you’re dreaming of a 0.5ct marquise, 1-carat round or a 2-carat oval, we source each stone with care — and with your story in mind.
Book a consultation in our Montreal atelier, Ottawa office or via Zoom (info@loftbijoux.com). We’ll guide you through everything, from reading a diamond report to falling in love with the stone.
Because every love story deserves a brilliance
