We at Henry D Johnstone appreciate that for many people, buying a diamond for our loved one or ourselves is often a very exciting but new experience. We are faced with so many different options to consider. Diamond education is based around understanding the four c’s (carat, cut, colour and clarity) which are considered the most important characteristics for buying a diamond. Purchasing a diamond is always easier when speaking to one of our gemmology experts in store. Contact us today to book an appointment or come in store.



Deciding on the shape or the cut of the diamond is one of the first steps. Round is the most popular stone with the most brilliance. The princess cut is square in shape that boasts a more contemporary edge. Cushion, oval and emerald diamonds are styles that are becoming a more popular choice for engagement rings. Ultimately there is no right or wrong answer, when it comes to selecting the cut of a diamond it's all down to personal preference and style.


The GIA grades all diamond colours using a scale from D (colourless) to Z (slightly coloured).The less colour, the rarer and more valuable. Here at Henry Johnstone we have a range of diamonds to suit your budget.


Clarity in diamonds is the assessment of flaws or imperfections. Virtually all diamonds have flaws that can't be seen by the naked eye. Diamonds are graded with an 11-point diamond clarity scale. It depicts the size, number, colour, and position of flaws that a skilled grader can make out under 10x magnification. The grade goes from flawless being the very best which is extremely rare to internally flawless, very very slightly included, very slightly included, slightly included and included.


Though there’s a difference between shape and cut, many jewellers use the terms interchangeably. The shape is the silhouette of the stone, while the cut refers to how the light hits the facets. Precise cuts ensure diamonds reflect light and sparkle. 



A common question we're asked is ‘how many carats should an engagement ring be?' or ‘what is the best carat diamond?'  The answer requires a  balance of your budget, style and expectation. When it comes to deciding how many carats your engagement ring should be, think about your partner, are they more of an extravagant or modest type - the ring should reflect this. If you find that your budget doesn't quite stretch as big as you would like you can trade some other quality factors for size. These decisions are much easier when working with a bridal expert in store and seeing the product.


After making the decision on the right diamond it is important that you have a guarantee that gives you the confidence to know that you are getting what you have paid for. Every diamond purchased at Henry Johnstone is accompanied by a diamond certificate from internationally recognised, independent diamond grading lab.