Book a Consultation –

Book a Consultation | Click Here


How to Choose a Diamond: Your Guide with Buying Tips

How to choose a diamond: A beginner’s guide

Purchasing a diamond is a big moment and investment in someone’s life.  You want to get it right and it is something you and your partner will. love long-term.  You’ve never had to research diamonds before and with so much information on diamonds it can get overwhelming.

We’re here to make the process easy so you can select the perfect diamond for you.

We’ve compiled the top tips our diamond experts share with their friends for you to demystify the 4C’s and to help you understand a diamond’s value and price.

Step by Step guide to choosing a diamond

  1. Select a Shape
  2. Pick a Carat Size
  3. Know about Diamond Quality
  4. Certification
  5. Natural vs Lab Grown
  6. Fun Facts & Quick Tips

Step 1. Select a Shape


The shape and cut of a diamond are often confused. The cut refers to how the facets align in proportion to each other and therefore how the light is refracted in the diamond. The shape is the appearance of the diamond, like the round brilliant cut is a round shape or the princess cut is a square shape.

Obviously, the shape will have the most impact on the look of the ring, so it’s wise to consider how it will look on your finger.  Also, the shape of the diamond will impact the price, as round brilliant cut diamonds are more expensive than fancy cut diamonds.

If you are ever unsure, the timeless round cut diamond is an excellent choice.  Other popular shapes are oval, princess, emerald, pear, cushion, asscher, marquise, radiant and heart cut.  Each shape has its advantages.


What is the natural shape of a diamond?

A diamond’s natural shape is an octahedron. Imagine two pyramids placed square end to square end. This lends itself to a square cut diamond, where there is less wastage when cut.

Diamond shape buying tip:

Round brilliant cut refers to a round diamond and is far the most popular. It offers the best scintillation and brilliance, in other words, the most sparkle, but there are many other options out there.  If you’re unsure what shape your partner would like, this is a safe one to go for.

What is the most valuable diamond shape?

The most valuable diamond shape is the round brilliant cut.  This is because it has the most facets of any other shape which requires more precision work and more wastage from the original natural diamond rough.  The brilliant cut is the only diamond that’s cut is graded by certification laboratories.  The upside of so many facets is you also have the most brilliance.

There are 9 main fancy shaped diamond cuts:

Princess Cut     1.  Princess cut diamond

Lady like (Square with center aimed facets, similar to a brilliant cut).  Works well for straight lined, geometric settings.

Oval Cut     2. Oval cut diamond

 Innovative (Just as you imagine).  Perfect for small fingers or to make your diamond look larger.

Pear Cut     3. Pear cut diamond 

Unique (Just as you imagine).  Ideal to create a long and slender look on your finger.

Emerald Cut     4. Emerald cut diamond

Glamorous (Rectangle with slanted corners and straight lined facets).  Perfect for a sleek and elegant style.

Radiant Cut     5. Radiant cut diamond

Diva (Rectangle with slanted corners and center aimed facets, similar to a brilliant cut).  Pretty in a feminine setting.

Marquise Cut    6. Marquise cut diamond

Dramatic (Pointed at both ends with a wider center).  When you’re looking for something unique.

Cushion Cut    7. Cushion cut diamond

Romantic (Just as you imagine, a cushion shape, soft square).  Perfect for a vintage inspired 

Heart Cut    8. Heart shaped diamond

Sentimental (The sweetheart cut). For the romantic at heart.

 Asscher Cut   9. Assher cut diamond

Vintage (Square with slanted corners and straight lined facets).  Ideal for a contemporary style.


Diamond shape selection tip:

For women with shorter fingers, elongated styles such as oval, pear or marquise diamonds will lengthen the look of their finger. Ladies with long fingers, shapes such as square or rectangular will create the illusion of shorter fingers. Women with larger hands are suited to a wider stone shape like a round or heart shaped diamond.


Often what you think you want and what suits your hand will be two different things so make sure you try some different styles on.


2. Pick a Carat Size


Do you have your heart set on a particular size?  Most people have the 1 carat diamond dream. When selecting your perfect diamond, determine what is the most important to you. Size, quality or a balance of both. Many people start with the size, as it’s visual, but when you get to know diamonds, quality will play a big part in the look of the ring or any other jewellery piece.

What is a carat diamond?

In diamond terms, carat refers to the weight of the diamond.  A one carat diamond equals 200 milligrams.  The diamond weight will also roughly determine the size of the stone also.

Is a higher carat weight better?

A higher carat means the diamond weighs more, which means it will likely be larger in size. The larger the diamond the more desirable it is.  

It is possible for two diamonds to weigh the same, but be very different in measurements.

Diamond price increases with the carat weight as larger diamonds are rarer, however two diamonds of the same carat weight can have very different values depending on the colour, clarity, shape and cut.


3. Know about Diamond Quality


Here is where the 4Cs of diamond play a part. The 4 C’s refer to a diamond’s Cut, Colour, Clarity and Carat. Each “C” plays a part in the overall look and value of a diamond. We’ve already discussed carat, so here’s an easy guide to the other 3 C’s.


Arguably one of the most important factors. Cut does not refer to a diamond’s shape, but it’s proportion and how well it is cut.  A cut grading on a certificate will take into account the symmetry and polish of the facets.  These affect the amount of brilliant, sparkle and fire in a diamond.   Grades range from excellent to poor.  If a diamond is not well cut, it can seriously affect the size and brilliance of your diamond.

Which cut of diamond is most expensive?

The most expensive diamond cut is the round brilliant cut.  This is because it has the highest wastage of natural diamond rough and has more facets than any other diamond.  The more facets the more precision work is involved with every individual diamond and the more brilliant (sparkly) the diamond looks.

The round brilliant cut diamond is also the only cut of diamond that is graded during the certification process.

What happens if a diamond is cut too deep?

When a diamond is cut too deep it affects the overall appearance in size.  A deep cut diamond will look a lot smaller than a well proportioned cut diamond.

When a diamond is deep cut it the look of the diamond will also be affected, causing it to look dull as the light is hitting the pavilion (top) of the diamond at a sharper angle causing it to reflect to another pavilion and then pass through to the bottom of the diamond.

What is the rarest cut of diamond?

An asscher cut diamond is the rarest cut of diamond.  An asscher cut diamond is a square emerald cut diamond.  It is a square shape with the corners cut off and the facets are step cut where the facets are straight and parallel to one another and have the appearance of steps.

Asscher cut diamonds have an art-deco feel with cropped corners and straight lines.


Diamond cut buying tip: 

Always opt for an excellent cut diamond as this will dramatically affect a diamond’s ability to deliver brightness.  Remembering facets are like tiny mirrors so when they don’t balance a stone’s overall appearance can be affected.

When looking at a diamond certificate, the cut grade is based on seven factors:  The GIA diamond cut grade is based on seven factors: brightness, fire, scintillation, weight ratio, durability, polish and symmetry. 


Aren’t all diamonds white?  Actually, no.  The colour scale reflects how colourless (white) a diamond is.  The less colour in the diamond the rarer and more valuable it is.  This is one of the most important factors in your diamond selection process.

The diamond colour scale starts at D (exceptional white +) and moves down the letter scale. As you travel further down the alphabet the more tinted/coloured the diamond is.

The higher the colour, the less difference there is between the colour grades.  The lower the colour, the easier it will be to tell the difference between the grades.

Bell & Brunt uses premium quality diamonds and strongly recommends selecting a D-G (exceptional white to rare white) if you’d like to have your diamond stand out looking amazing years down the track.

What is the best diamond colour?

The best diamond colour is D. The D colour is completely colourless and is classified by HRD Antwerp as exceptional white +.

Diamond colour is all about what you can’t see.  D-F diamonds are rated as colourless by the GIA and these are the absolute best you can get.

The higher the letter, the better the diamond colour.

Which is the most expensive diamond colour?

The most expensive diamond colour is red.  They are so rare that under 30 true natural red diamonds exist.  All fancy coloured diamonds such as pink, blue, yellow and green are rare and make them more valuable than white.

For white diamonds, D is the most expensive diamond as it is the rarest and highest grade.

Diamond colour buying tip:

When buying a white diamond, stick to D-G and not below. The higher the colour grade the less difference there is between them. Something in the exceptional white range will still hold its shine across a room even after it’s been worn a thousand times. They are also more likely to hold their value.


As natural diamonds are formed over up to 3.6 billion years in the earth, inclusions (birthmark characteristics) occur inside the diamond during the growth.

 These are minerals that are contained within the diamond and can be either another diamond crystal, carbon, garnet or peridot. Inclusions can also be natural strains within the carbon structure during formation, diamond growing pains, like twinning wisps and feathers. 

This is probably the least visually affecting aspect of the diamond as the inclusions are not often visible to the naked eye.

Much like with colour, the higher the clarity, the less variance there is between gradings, the lower the grading the larger the difference.  The higher the grading, the more rare and valuable the diamond is.  Clarity gradings are based on 10x magnification

The clarity scale starts with IF (internally flawless), VVS1-2 (very, very slight inclusions), VS1-2 (very slight inclusions), SI1-2 (slight inclusions), I1-3 (inclusions).  

VVS-VS gradings will have extremely tiny inclusions and be difficult to find with a loupe (10x magnification). SI graded diamond inclusions will be easier to spot under magnification and I graded diamond inclusions will be visible without magnification (with your naked eye). Bell & Brunt uses premium quality diamonds and strongly recommends VVS – SI2 in clarity.  

Commonly asked questions around diamond clarity generally include:

Which one is better - VS1 or VS2?

Although there’s not a massive difference between these two gradings of diamond clarity a VS1 diamond is better than a VS2.  The lower the number(or letter) the better it is.  

The higher the quality of diamond clarity the less difference there is between the two.

Is H-I diamond colour good?

H-I colour diamonds are nearly colourless.  They are a good middle range diamond colour, not premium, but not too tinted.  If you are looking to increase the size of your diamond while staying in your budget, this is one option you could consider.

What are the worst diamond inclusions?

The worst diamond inclusions will be graded as I (Included) or P (Pique – French for Included).  These will be obvious to the naked eye, meaning you won’t need any magnification in order to spot these inclusions.  

There are some challenges when it comes to a heavily included stone, being the stone may be more likely to chip when being set.  Black carbon inclusions will also stand out the most when looking at the diamond.

Remember, every diamond is unique and not all inclusions are the same.  Some will be white, some dark.  Some will be tiny dots, others a line or a cluster, that is why it is so important to see for yourself.

Want to hold the diamonds and spot the inclusions? Call us to book an appointment

4. Certification


A diamond certificate is an unbiased grading report from a scientific source such as GIA (Gemological Institute of America).  Here diamonds are shipped to the gemological laboratories after being cut to have it’s quality verified. 


The lab will provide in-depth detail, authenticating the diamond’s cut, colour, clarity, carat, fluorescence, polish and symmetry.  Some diamonds will also include a laser inscription on the girdle (edge) of the diamond detailing the unique certificate number.

Not all laboratories are considered equal and it is possible for certificates to be generous on the gradings. Bell & Brunt recommend GIA and HRD as trusted certification sources.

Purchasing a diamond with a certificate gives you the extra layer of confidence in what you are buying.  However, always examine the diamond you are buying in person to be certain that the certificate that comes with the diamond is for the diamond you are buying.

How do I get diamond certified in Australia?

You can get your diamond certified by the Diamond Certification Laboratory of Australia through your jeweller.  DCLA is equipped to test and identify diamonds to international diamond council standards.  If you have one you would like graded then you can arrange to have your stone certified by DCLA through your jeweller.

Is it ok to buy a diamond without a certificate?

Not all diamonds are certified.  Only a select few will go through for laboratory testing after the cutting process.  The diamonds not certified will be sold in graded parcells.  

The Jewellers Association of Australia has rules around diamonds over a certain size, colour and clarity gradings requiring a certification.  

It really depends on how much you trust your jeweller.  A diamond without a certificate will save you a few hundred dollars, but one with a certificate will give you peace of mind.

Diamond certification buying tip:

Always see the diamond yourself to assess if it is the one for you. Trust what looks best for you rather than what the paper says. Be careful buying diamonds online. Just because it has a certificate doesn’t mean the certificate is for the diamond you are purchasing.  To be sure, opt for a laser inscribed diamond. This will have the certification number on the girdle of your diamond.

5. Natural vs Lab Grown

Natural diamonds – 3 billion years in the making

  • Billions of years old (up to 3.7 billion years)
  • 160 kilometers beneath the Earth’s surface
  • Extreme conditions
  • Before life on earth 

The natural diamonds have become the universal symbol of love, strength and wonder.  Their story and history can become part of yours.

Here’s a little about the history of natural diamonds:

 Diamonds are much older than Earth’s first plants and even atmosphere.  

The mystery of Diamonds would have remained a hidden wonder, deep within the Earth, had it not been for ancient volcanoes that exploded to the Earth’s surface. They are an incredible feat of nature.  Many things had to line up just right for diamonds to form, let alone make it to the surface. They were born with extreme pressure, heat and time with only a small portion that were able to make the journey to the Earth’s surface.  There is little more rare or beautiful than a diamond’s beauty.  There is simply nothing that compares.  Just like great art, diamonds are rare and no two alike.  Only 30% of diamonds that are found are of gem quality.  

Fun fact # Diamonds of 1 carat and larger are so rare, all of them discovered worldwide a whole year would fit into an average sized exercise ball!

Synthetic or lab grown diamonds:

Synthetic diamonds go by many different names — lab-grown, lab-created, lab-made and even engineered diamonds. These names all point to the fact that synthetic diamonds are created in a laboratory or factory rather than occurring in nature and mined from the earth.

How long does it take to make a lab grown diamond?

It takes approximately 2-3 weeks in a lab to create a synthetic diamond.  This is done by one of two different methods, either a high pressure, high temperature or by chemical vapor deposition.

High pressure, high temperature method mimics the conditions of natural diamond formation in the earth using temperatures which are 1300-1600 degrees celsius and pressure equivalent to that exerted by a commercial jet airplane if balanced on the tip of a person’s finger.

Chemical Vapor Deposition uses carbon-containing gas that is pumped into a vacuum chamber depositing on a diamond seed and crystallizing as a synthetic diamond.

Are lab grown diamonds eco-friendly?

Although lab-grown diamonds are marketed as eco-friendly, the carbon emissions are 3 times more than natural diamonds on average. Synthetic diamonds require large quantities of energy to replicate the extreme heat and pressure that happens naturally in the earth.

Diamonds are grown in labs in countries including China, Singapore and the US, places that lean heavily upon fossil fuels for energy. 

The huge amount of power needed to create a diamond can lead to significant output in carbon pollution if the energy source is dirty.

Are natural diamonds more expensive?

Yes, natural diamonds are more expensive than synthetic diamonds. This is due to their rarity and the skill that goes into mining, cutting, polishing, grading them.  However, it depends on the quality of the diamond, each one will be valued according to its size, colour and clarity amongst other factors.

How much is 1 carat natural diamond?

A 1 carat natural diamond is approximately $15,000.  The price of a 1 carat natural diamond depends hugely on the colour, clarity and cut grading of the diamond along with the shape.  But for a premium quality 1 carat diamond, this is around the price.

Are lab grown diamonds as good as natural diamonds?

Lab grown diamonds are not as good as natural diamonds. There’s something romantic about the natural diamond journey, created by forces deep within a young earth. So many factors had to align perfectly for diamonds to form in ancient earth and be carried up the surface. These conditions no longer exist.  All the diamonds the earth will form already exist.

These incredible billions of year old crystals will be the oldest thing you will ever touch and they are incredibly rare. All of the gem-quality diamonds that have been mined would fit into one London double-decker bus. They also pass through multiple stages of skill being cut, polished and graded.


The value of your diamond is also important, as it is a big investment.  While natural diamonds are rare and will increase their value, the more synthetic diamonds are made, the less expensive they will become and will decrease in value over time, already decreasing in value over the last few years.

6. Fast Facts & Quick Tips

Fun fact: Round brilliant cut diamonds are the only shape with established cut parameters, all other shaped diamonds have standards, but are determined by the cutters rather than GIA.  The cutting standards makes them slightly higher in value than fancy shaped diamonds, coupled with the larger wastage of diamond to create this supreme shape.

Buying tip: A well-cut diamond reflects maximum light—a sparkle you can see across a room.

Buying tip: Trust your eyes!  Some diamonds will just stand out more than others so don’t just rely on what a certificate says.  As clarity differs in appearance as well, pick the diamond that you’re most comfortable with.

Fact: Two diamonds of equal carat weight can have massively different values when the other three Cs are considered.

Fact: Two diamonds of equal carat weight can look very different in size.  A poorly cut diamond can look up to a third smaller than a well cut one.  

Fact: A diamond cut too shallow or too deep will bend and refract the light in different ways and it will perform less in terms of brilliance, fire and scintillation

Setting tip: Set your diamond with white claws to keep it looking as bright and white as possible, even if you like the idea of yellow or white gold, the band will still give you the colour.

Buying tip: Size isn’t everything.  A top quality diamond will stand out across a room and still look incredible after washing your hands 100’s of times.

Buying tip: Diamonds have price jumps at certain carat weight marks eg 1/2 carat, ¾ carat and 1ct.  If you’re trying to keep to a particular price point, selecting a diamond just shy of those marks is a great way to reduce the price.  Visually, the diamond will look only slightly different, but you may be able to go up a higher colour or clarity grade instead.

Buying tip: You should feel completely confident and excited by your choice of diamond.

Buying tip: You can always chat, call or zoom with our diamond experts.  They are pros at simplifying the information, answering any questions you have and helping you to feel confident to find your perfect diamond.

Leave a Comment

Your email address will not be published. Required fields are marked *






Table of Contents

Scroll to Top