Diamond Buying GuideAt Macintyres we believe that the best decisions are made with an informed mind. We are proud of our expert diamond graders and gemmologists and we believe that like us, our customers want quality and value. All our diamonds are individually chosen by our qualified diamond graders to ensure the best possible value for money. We hope the following information will help you understand the characteristics that affect the value of a diamond.

Between 950 and 1500 million years ago, deep inside the earth, at unimaginable temperatures and huge pressure, a tiny crystal slowly began to grow.  Before man or even dinosaurs walked the earth a tiny piece of the hardest substance on earth begins its longest journey. Forced to the surface by a volcano, washed by billions and billions of raindrops down mountain sides into river beds and finally to the sea. Discovered by man and separated from the 95% of diamonds that are not gem quality it is cut to precise guidelines to release the brilliance and fire within, finally achieving its destiny… to be your engagement ring.

If you imagine a four-sided pyramid, with each side being a diamond characteristic, the more readily available diamonds form the base of the pyramid while the rarest diamonds are at the top. Keep this in mind when you are selecting your diamond. Your selection of characteristics will determine rarity and value. Our job is not to find the perfect diamond, our job is to find the perfect diamond for you.

Conflict Free Diamonds

We work only with the most reputable and regulated diamond suppliers, so you can be confident your diamond has been mined and processed in an environmentally and socially conscious manner.

Lab Grown Diamonds

Lab grown diamonds are synthetic diamonds manufactured by man in a laboratory using intense heat and pressure. They possess all of the features of natural diamonds but without the rarity and hence the price tag. Macintyres stocks an attractive range of certified, high quality lab grown stones in-store. You can choose from our selection of ready-made lab grown diamond engagement and dress rings. Or, choose a loose lab grown from a variety of sizes and cuts and have it set in a mount of your choice. View our beautiful collection of rings and jewellery in-store or contact us for further information.

Certified Diamonds

Many of Macintyres’ diamonds come with independent certificates confirming the quality and cut grade of the individual stone. These certificates are prepared by diamond grading laboratories of international renown such as GIA, HRD, IGI and EGL. These labs will also confirm that the diamonds are natural and have not been treated in any way. Beware of other diamond sellers who provide obscure certificates or self-certify their own stones.

Certified Diamonds

Cut and Shape

When you think of the cut, you probably think of the shape of the diamond. You are partially correct but while cut does refer to the shape it also refers to the proportions of how the diamond is actually cut. Diamonds are cut into many different shapes, reflecting not only popular taste but the proportions and quality of the rough diamond.

The most popular diamond cuts include Round, Oval, Square, Princess, Emerald, Baguette and Marquise. Many speciality shapes are also available.

A diamond’s overall proportions as well as the size and placement of its many reflective surfaces or facets, also play a large part in “cut”. The consistency and balance of these can greatly affect how the stone captures light and reflects it back to the eye.

Diamond Cut and Shape

Diamond Cut Explained


The size of the diamond is measured not by its dimensions but by weight. One carat, the traditional unit of measure for diamonds, is equal to 0.2 grams. You may also hear the weight of a diamond referred to in points. A point is equal to 1/100 of a carat. Therefore a 75 point diamond equals 0.75 carat. Diamonds of equal weight may appear slightly different in size, depending on their depth and proportions. Because they are quite rare, larger diamonds of gem quality are much more valuable.

Diamond carat weight


With the exception of some fancy coloured diamonds, the most valuable diamonds are those with the least colour. The colour scale for transparent diamonds runs from D-F (colourless), G-J (near colourless), K-L (faint yellow) to Z (light yellow). Completely colourless diamonds are rare. When diamonds are formed with traces of other minerals, rare and beautiful colours can result. These “fancy” colours range from blue to brilliant red, brown, pale green, pink and violet. Because of their rarity, coloured diamonds are highly desirable and may be quite valuable.

Diamond Colour Chart


Diamond clarity is measured by the existence or absence of visible flaws. Tiny surface blemishes or internal inclusions, even those seen only under magnification with a jeweller’s loupe, can alter the brilliance of the diamond and thus affect its value. Clarity levels begin with flawless (F&IF) and go down to Very Very Slight (VVS1 &VVS2), Very Slight (VS1 & VS2), Slightly Included (SI1 7 SI2) and Included (I1 & I2 & I3).

History of the 4Cs



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