Colour Grade

Diamonds are valued by how closely they are to colourless – the less colour, the higher the value (with the exception of fancy colours ie pink, blue). Most diamonds found in chain jewellery stores contain a slight to significant tint of yellow or brown. Diamonds sold in higher class stores usually range from colourless, to near colourless.

The scale begins with the letter D, representing colourless, and continues with increasing presence of colour to the letter Z. Diamonds are colour-graded by comparing them to stones of known colour under controlled lighting and precise viewing conditions.

Many of these colour distinctions are so subtle that they are invisible to the untrained eye. But these slight differences make a very big difference in diamond quality and price.

Global Diamond’s Tip

We recommend purchasing a diamond between the grades of D (colourless) to G (Near colourless). Any diamond graded either “I” or above starts to have prominent signs of yellow coming from the diamond. These yellowing diamonds should be far cheaper than a diamond with a better colour grade, but they don’t have the same beautiful look.  Sacrifice a bit of size for a better colour grade.

Also note that you cant spend too much money on getting the perfect colour. D coloured diamonds are truly amazing. However if you cant quite afford a D coloured diamond but still want an amazing look, we tend to recommend F colour diamonds for the slightly more price conscious, who still want an amazing look.

Category: Diamond Education

Clarity Grade

It’s all about what you can’t see

By the nature of their formation in the earth, most diamonds contain unique imperfections called inclusions. Diamonds with very few inclusions are rare and, of course, rarity affects a diamond’s value. Using a grading system, diamonds are given a clarity grade that ranges from flawless (FL) to prominent inclusions (I2). Every diamond is unique, but none are absolutely perfect. In determining a clarity grade, diamond graders consider the size, nature, position, colour, and quantity of clarity characteristics visible under 10x magnification.

Common Mistake

Often a first time buyer will mistaken the word clarity for a diamond’s sparkle and radiance. These elements are determined by the diamond’s cut.

Global Diamonds’ Tip:

In general, any diamond with a clarity grade of I1-I3, has inclusions visible to the naked eye. Global diamonds recommends avoiding diamonds in this scale, and advises to purchase in the SI2 grade or higher.

However further to this, a flawless diamond is not necessarily any more beautiful to the eye than an SI2.  For this reason, clarity is a grade you can keep down in the SI grades putting your budget towards other elements of the diamond such as better colour or cut.

Also note that grading for clarity is a subjective matter.  We see many diamonds that say they are SI2, but on inspection they actually look more like I1 grade.  This is where it is important to know that the seller of the diamond actually has the diamond in hand, or is willing to get it in from offshore, without any down payments.  You don’t want to end up with a diamond with inclusions that are visible to the naked eye.

Category: Diamond Education

Carat Weight

Diamonds and other gemstones are weighed using metric carats with one carat weighing about 0.2 grams. It is important to note that two diamonds of equal weight can have very different price values depending on the other characteristics of a diamond’s 5Cs: clarity, colour, cut, and crystal structure.

Global Diamond’s tip:

Never sacrifice quality for size. There is nothing worse than your partner having to continually tell her friends that her diamond doesn’t sparkle because it needs a clean. A diamond with great fire and sparkle will look visibly larger to the eye than a diamond with no lustre. A diamond’s size should be the last piece of the puzzle. Once you have chosen the right grades for yourself, the size of the diamond should be dictated by the budget you have set.

We have also had clients say they saw a 1.00 carat diamond that looked a lot bigger than another 1.00 carat diamond. What this simply means is that the particular diamond was cut with a very wide table, but a very shallow depth. This type of cut may make the actual diamond size look big, but the poor cut proportions will make the diamond look dull and lifeless. It is far better to have a diamond that is cut properly to the correct proportions, as this gives the diamond life and fire.

Another very important issue to note with carat weight is when jewellers talk about total carat weight. This is the total weight of all diamonds within the piece of jewellery. It should be strongly noted that diamonds go up exponentially in value the bigger they get.  Therefore, several small diamonds that make up a 1.00 carat total are far less valuable than one large diamond that weighs the same amount.

Category: Diamond Education

Crystal Structure

There is a “5th C” of diamonds seldom discussed, but very important to understand before making any diamond purchase. This is called “Crystal structure”

Not all diamonds have the same quality crystal structure. This means that two diamonds with exactly the same grades may have a completely different look and value. A poor crystal structure leaves a diamond looking milky and lifeless, even if the other 4 grades (4 C’s) of the diamond show good quality. A diamond with a very good crystal structure will have transparency through the stone, making it look full of life and beautiful.

The issue for the consumer is that there is no accounting for crystal structure within a diamond grading report. It is up to the individual to recognise the difference, or use an experienced and reputable company from whom to purchase.

We are beginning to see more and more diamonds enter the jewellery market that should have been rejected and used in the industrial product market (remember poor quality diamonds are used for industry tools such as grinding disks etc.)
How does this effect your purchasing decision?

It does so in two ways

1. When buying online, make sure you are buying from a supplier who has physically seen all the diamonds being sold in their database. Try to avoid merchants who list from a simple global database. A global database is a listing of diamonds for sale from diamond suppliers around the world. The point here is, even the most experienced diamond salesman cannot guarantee the crystal structure of a diamond if he/she has not seen it themselves. Never pay a deposit or buy a diamond from a merchant without seeing the diamond in the country first.

2. Never buy a diamond from a classic “Trade-me” type seller who has limited diamond knowledge or access. Unfortunately, through lack of experience, these sellers often find themselves associated with suppliers of industrial diamonds. These suppliers are now finding it more financially rewarding to sell their industrial grade diamonds in jewellery sets to E-bay and Trademe stores alike.

When purchasing from Global Diamonds, you are using our experience and reputation to ensure you only purchase a diamond with excellent crystal structure.

Fluorescence in Diamonds – What does this effect?

“Those diamonds that produce a visible reaction when exposed to ultraviolet radiation. In laboratory experiments with both trained gemologists and individuals with no diamond experience (meant to represent the jewellery-buying public), no relationship was found between fluorescence and a diamond’s overall appearance. Diamonds with a strong or very strong fluorescence are a better value for the end customer because the market prices them slightly lower than diamonds with faint or negligible fluorescence”.

So What Does that mean for My Diamond……

Fluorescence is a greatly misunderstood concept. Fluorescence is the reaction of trace minerals within the diamond that cause the diamond to glow when exposed to ultraviolet light. In the laboratory, special ultraviolet lamps are used to check for this but the sun is also a source of ultraviolet rays so diamonds will react in daylight as well. About one third of all diamonds fluoresce. Of these, the most common color is blue, but diamonds can fluoresce other colors. More than 95% of those that do fluoresce will fluoresce blue. The next most common color is yellow. Any other color of fluorescence would be rare.

There are some educational sites or selling sites that discuss fluorescence as a negative value factor. When a diamond fluoresces blue it has a tendency to appear higher in color than its true body color. This is a good thing. However, many years ago, fluorescence was thought to be a negative, and the reasons can only be speculative. One such reason was that it was thought that perhaps the color grade assigned was lower than its apparent color, so people were fearful that they would be paying too much for a diamond. For example, a J color diamond might look like an H or an I color if it had fluorescence. But as long as the diamond is correctly graded as J, then the fluorescence is really like a bonus. The diamond looks higher in color than the price suggests.

Two factors should be considered regarding fluorescence. The first is the color of the fluorescence. If the diamond fluoresces blue, it may be a positive factor since it will make the diamond look whiter. However, note that there is still a stigma against fluorescence and some people will simply not buy the diamond and some sellers will offer a discount for fluorescent diamonds in the higher colors. If the diamond fluoresces yellow, this is a negative factor because the diamond will look lower in color in ultraviolet light.

The second factor is the strength of fluorescence. The range of strengths as reported on laboratory grading reports is None, Faint, Medium, Strong, Very strong (As shown below). Some labs use the term Negligible for any diamond with no fluorescence or faint fluorescence. Sometimes when a diamond has very strong fluorescence, the diamond will have an “oily” look to it, even in normal lighting conditions. When this happens, a negative value is expected. The range of discounts that might be realized are anywhere from 0% to 15%, but a large discount is rare. Occasionally, a slight premium of 1% to 3% might be added for a diamond that is in the lower color grades but exhibits fluorescence.


If you have any further questions about Fluorescence or any other Diamond matters please reply to this blog or contact us through the Contact Us tab and Get in Touch.

Cast vs Handmade jewellery

In this topic, we refer to handmade jewellery as jewellery that has been started from a block of metal and formed into a piece of jewellery by hand.  Some jewellers like to refer to hand finished jewellery as being handmade.  Hand finished is where the jewellery has been made by some other process other than by hand, and is then finished off by hand to some description.

Cast jewellery is just as it is titled.  Moulds are made of the jewellery style and then gold is poured into these moulds to form the jewellery.  These castings are then usually cleaned up and polished by hand.

So what is the difference.  Cast jewellery is effective for mass production and is generally the way your typical chain store operates.  The upside is that the process reduces the labour cost and therefore the final price.  The downside is typically one of quality, or durability.

Handmade jewellery is more labour intensive and therefore more expensive.  However the biggest upside is that the gold or platinum has been work hardened and the jewellery will last longer as a result.  You cant compare the price of a handmade to a cast piece of jewellery.  The extra price in a handmake is easily made up for by the quality of the ring and the longevity of the jewellery.




Category: Metal Education

Platinum vs Gold

Platinum vs Gold is a very personal choice.  Platinum is generally more expensive than gold as it is heavier (therefore uses more) and it is usually 95% pure when made into jewellery, compared to 75% for 18ct gold.  However there are pro’s and cons to both.

Platinum will wear better than gold over the decades as it is a more dense metal.  Platinum is a much whiter metal than white gold, but it does have a grayish appearance when it wears.

White gold has a yellowish appearance in its raw form.  This is why most white gold is rhodium plated, which gives it a very white appearance.  Rhodium plating is however only a temporary plating and will wear over time. This is why we use a Platinum based white gold which is white even in its raw form and doesn’t need a Rhodium plating new or at any point over time.

From a personal point of view, we feel that a brand new white gold ring looks sharper than a brand new platinum ring.  However the real benefit of a platinum ring is its durability over time.

All in all, both metals produce a stunning look and it is important to keep your jewellery clean and polished.

There has always been this perceived belief that Platinum is a superior metal to gold, and it is commonly used by the rich and famous.  Perceptions aside, white gold can look just as stunning and in many cases it is still a preference in its look.

Does Gold scratch easier than Platinum

There is a bit of a myth out there that Platinum is harder than gold, and therefore doesn’t scratch as easily.  Platinum is actually softer than gold but it is more dense in nature.  Therefore it scratches just as easily as gold but the metal only displaces rather than wears away with a scratch.

In conclusion, both are very nice metals, but both need to be maintained to look their best.  The cost of maintenance is very similar.  Platinum will last longer over time and has a heavier feel to it.  The rest of the decision is just a personal choice and to many, a cost related issue.

Avoid the ‘8’ Mistakes People make when buying a Diamond Ring

The following Guide is an absolute must read before you purchase any diamond ring from any store or on-line shop.  It spells out the pitfalls in black and white and in simple terms.  We all love quality, but at the same time, we are all price conscious.  Big marketing campaigns can murky your decision making process, as can plain lies and misinformation.  This guide tells you a few things to look out for and will ultimately ensure you end up with a stunning diamond ring at the right price.

Download your free copy today and read it a couple of times before you make any big decisions.  If you have any questions after you read the guide, please feel free to contact us by phone, email or live chat.


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Avoid the 8 Mistakes People Make When Buying a Diamond Ring

Category: Guides

Synthetic and Man-made Diamonds vs Natural Diamonds

Round brilliant polished diamonds.We often get comments from customers asking why they should by a real diamond vs a man-made diamond. Their argument often involves the following points:

  • A man-made diamond is much cheaper than a real diamond
  • A synthetic diamond has more brilliance than a real diamond (particularly Moissanite)
  • A man-made diamond is almost as hard as a real diamond (paricularly Moisannite)

Well here is our typical answer to dispel a few myths…

A man-made diamond or synthetic diamond is in cases much cheaper than a real diamond, however they are well over priced for what hey are. Many years ago we saw the introduction of Cubic Zirconias which were cheaper than diamonds but still well over priced for what they were. They have now come down to their true value at about $5 for a bucket load of them. So the price argument becomes redundant, a man-made diamond will always fall back to its natural price, which is unfortunately about worthless. We see people come into our store all the time where they purchased a diamond many years ago for say $200 which the diamond is now worth say $5000. The Cubic Zirconia they bought years ago for $50 in now worth Nil.

The second point is the claim man-made/synthetic diamonds have more brilliance than a real diamond (particularly moissanite). The truth here is that they do, but diamonds have never claimed to have the highest refractive index on the earth. The beauty of the diamond comes from the unique refractive index that it does carry. Nice and brilliant, but it doesnt look like you have a disco ball or rainbow on your finger. So for the Moissanite manufacturer to claim that their product has a far higher refractive index than diamonds, is to claim their product looks nothing like a diamond, so why do they call it a synthetic diamond??

The last point is the hardness of Moissanite vs Diamond. In the official Mohs scale of hardness, a diamond carries the top level 10 out of 10 and Moisannite carries approx 9. This seems to be close, however the scale is not one of a straight line, rather it increases exponenitally. In simple terms, a diamond is up to 100 times harder than its nearest man-made or synthetic creation. Number 9 in the Mohs scale is closer to number 1 than it is to the top level 10.


Coloured Diamonds: Good, Bad, or Fad?

Round brilliant polished diamonds.When most men consider purchasing a diamond engagement ring, they automatically picture a colourless diamond, and rightly so. Colourless diamonds are the most popular and perhaps most desirable of all diamonds, but they aren’t the only stones available. Diamonds occur in a variety of different colours that can be extremely appealing to many women.

So, why if they are so fabulous, haven’t you heard much about them? Could it be they are just a fad? Let’s find out.


The Truth About Coloured Diamond Rings

  • They are Rare- One of the main reasons coloured diamond engagement rings are unique and not generally seen is due to the fact that they are actually rather rare. Now, there are stones which are enhanced artificially, but that’s not what we’re discussing.
  • They Come in Various Colours- Coloured diamonds can be found in a variety of colours, including blues, greens, blacks, purples, and yellows. The rarest diamond colour is pink, and is only found in the Australian Argyle diamond mine, which is a mine that produces all but 5% of the diamonds in the world. Regardless of their colour, these diamonds are made by forming near mineral deposits. The type of deposit and the position of the deposit determines the colour of the diamond.
  • Their Use is Affected by Prejudice- While these diamonds are beautiful, especially when used in engagement rings, many individuals are not keen on them. This is because they have been taught that white, or more appropriately, colourless diamonds are the best. While colourless diamonds are indeed beautiful, it never hurts to add a bit of colour to your world.
  • Some Coloured Diamonds Didn’t Start Out Beautiful- Because diamonds that have colour are generally more expensive and rare, many individuals use colour enhancement to bring out the colour, or change the colour, of their diamonds. This process is risky to the diamond, however, and some diamonds cannot be enhanced.

While fashion trends do tell us whether or not wearing coloured diamonds is ‘in style,’ these beautiful diamonds should not be considered a fad. Rather, they are unique gems that are part of the vast and beautiful diamond family.

If you are thinking of purchasing a diamond, don’t let the latest fads or trends be a part of your diamond decision. Whether you are looking for a colourless stone or something a bit unique, it’s a highly personal decision. If you are unsure, the traditional, colourless diamond in a round cut is by far the most brilliant of all. You can’t go wrong with that one.