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Diamonds are the most well-known gemstone in the world, it is the birthstone of April, name derived from the Greek word ‘adamas’, meaning invincible. This is probably a reference to the outstanding hardness of a Diamond and its mythological properties of protection against poison or attack. Our Ultimate Diamond Guide can be found under our Jewellery Stories section.


Ultimate Diamond Buying Guide

Read our Ultimate Diamond Buying Guide which explains more about how each individual component affects Diamond Pricings. In our experience as gemstone dealers, we have amassed a lot of industry knowledge after seeing thousands of Diamonds. Predominantly as gemstone traders, we know what to look out for and would like to share our comprehensive knowledge to our clients.

This guide includes our opinion and experience in the industry - appraisals from working in auctions and pawn brokering. Our Ultimate Diamond Guide will ensure that all your questions are answered, and you will have the theoretical knowledge of a Professional Diamond Grader and market expert after reading.

History & Lore

Until the middle of the twentieth century, there was no agreed-upon standard by which Diamonds could be judged. GIA created the first, and now globally accepted standard for describing Diamonds: Color, Clarity, Cut and Carat Weight

A Diamond’s 4 C’s are the main components that makes Diamond so attractive to our eyes. The creation of the Diamond 4 C’s meant two very important things: Diamond quality could be communicated in a universal language, and Diamond customers could now know exactly what they were about to purchase.

Today, the 4Cs of Diamond Quality is the universal method for assessing the quality of any Diamond, anywhere in the world. Different laboratories grade diamonds on a slightly different scale, of all reports, GIA reports are the most trusted and widely used report.

The biggest rough diamond of gem-quality ever unearthed is the Cullinan Diamond, weighing in at an astonishing 3106.75 cts. This incredible rough is then ordered by King Edward VII of the United Kingdom in 1907 to cut in the hands of Asscher Brothers in Amsterdam. The 3106.75 cts rough yielded 105 diamonds including the world-famous Cullinan I and Cullinan II, the two biggest of the 105 diamonds, that is on display as part of the crown jewels. Other notable big diamond roughs include The Lesedi La Rona at 1,109 cts, The Excelsior Diamond at 995.2 cts and The Star of Sierra Leone at 968.9 cts. 

There is also a term known as Blood Diamonds. Blood diamonds refers to diamonds mined in a war zone, mostly African countries, and sold to finance war efforts or insurgency. Unlike common misconception that they look different, they don't: they have the exact same appearance and qualities of a normal Diamond. 

The Kimberly process that started in 2002 greatly reduced such sales of Diamonds, but even to this day, there is an estimated amount of 1% of diamonds are still coming from conflicted sources.



Diamond Colour is graded in terms of how colourless a diamond is. GIA grades Diamonds from D to Z, with D being the most colourless, and Z containing noticeable brown or yellow tint. Colour D-F is considered colourless under the GIA Scale, G-J, near colourless, K-M faint yellow/brown, N-R very light yellow/brown, S-Z light yellow/brown.

Diamonds that are in saturations beyond this chart are graded on the Coloured Diamonds scale. Diamonds can come in every colour of the rainbow, and most of the Coloured Diamonds are much rarer than those on the colourless scale. Colourless Diamonds are graded on the face down colour, as scintillations from face up might obstruct accurate views on the body colour of the Diamond.

We recommend getting Diamonds of colour H and above, these Diamonds to us, looks colourless or very close to colourless. I or J diamonds, though still belonging to the near colourless scale, are more obviously tinted.

For reference, as trained Gemologists, we can tell the colour range of a Diamond (D-F) or (G-H and I-J) just from looking at the Diamond alone. However, when it is set into jewellery, it makes it a lot harder and unless compared with another reference stone side by side. Hence when choosing a Diamond colour, it is important to know what you are looking for and what you prioritise, compared to other components if you are trying to get the best deal.

Read our Ultimate Diamond Buying Guide which explains more about how colour and its setting affect a Diamond’s price.



GIA grades diamonds in 11 clarity grades, which refers to how free the diamond is from inclusions and blemishes. The cleaner it is, the more valuable and rarer the diamond is. The clarity grades used are:

· FL (Flawless)

· IF (Internal Flawless)

· VVS1 (Very, very slightly included 1)

· VVS2 (Very, very slightly included 2)

· VS1 (Very slightly included 1)

· VS2 (Very slightly included 2)

· SI1 (Slightly Included 1)

· SI2 (Slightly Included 2)

· I1 (Included 1)

· I2 (Included 2)

· I3 (Included 3)

GIA grades based on the size, location, and relief of the inclusion, for example, a colourless crystal and a black crystal will have different impact on the clarity grade. One thing to note is, when you purchase a Flawless Diamond, and say you set it into a setting and wear it, it could eventually become a internally flawless stone, due to the possibility of scratching the surface during normal wear.

In our opinion, clarity is the second most important factor (behind cut) to the beauty of a Diamond, and you should engage the assistance of an expert as even in the same clarity grade, the appearance could be vastly different. There could be two stones with the same grade D VS2, but one exhibits no visible black inclusion on the face up, while the other one exhibits a noticeable black inclusion, and reflections of it on the side.

Generally, we recommend our clients who focus more on prices, to get a VS clarity, because the difference between a VS and a VVS Diamond is due to the presence of crystal inclusion. Thus we can find a VS Diamond with a small crystal inclusion on the side that is very difficult to observe even under a 10x loupe in the expert’s eye, which will look very clean and brilliant, while omitting the price tag of a VVS grade Diamond. The certificate alone will not tell you how the blemish or inclusion affects the appearance of the Diamond, but the stone and a proper jeweller will and should.

For reference on how miniscule Diamond inclusions can be, a VVS Diamond would take around 5 minutes under a 50x microscope to locate, a VS Diamond on average would take 15 seconds or more. However, when used a 10x magnification loupe, a VS diamond would take a much longer time, sometimes even 10 minutes to locate the inclusion. Could you imagine trying to find the inclusion with just your naked eye?


Diamond cut refers to how the Diamond facets are being cut which include the angles, the proportions, the symmetry, brilliance, fire, scintillation and finishing details of the Diamond. These components directly impact how a Diamond sparkles, which is what makes Diamond so fascinating to our eyes.

A poor cut Diamond and an excellent cut Diamond will look vastly different to our eyes even if all other 4 C’s stays constant. GIA grades cut on a scale of Excellent, Very Good, Good, Fair and Poor, separated into Cut, Symmetry and Polish

In the current market, some people are looking for what we call 3 Excellent (also known as Triple Excellent), which means Cut, Symmetry and Polish are all excellent, and these usually carry a premium on its price. As excellent cutting stones come in a range, these standards may not be a sure way to guarantee a spectacular stone, but it promises a stone that will be aesthetically presentable

This is also why a competing laboratory AGS refined GIA’s grading system to include an ‘Ideal’ grading above the excellent. However, do note that there are some overlaps: AGS Ideal falls within the GIA Excellent, but the AGS Excellent would overlap with GIA Excellent and Very Good. Based on our experience, in terms of percentage, around one third of GIA excellent cut Diamonds will fall in the AGS Ideal range. To know if your GIA excellent cut Diamond qualifies as an AGS ideal, you would then have to analyse each individual proportion, angle etc. that only a properly trained Gemologist or Diamond Grader with sufficient market expertise can differentiate.

Round diamonds are priced at higher prices than diamonds of other shape, due to market demands and the fact that cutting a Round Diamond will most of the time save less weight from the rough. The reason why every Diamond is cut differently, and not to the best proportions is due to the limitations of the rough and weight saving. For example, a 0.75 carats excellent cut Diamond will have a significantly higher price than a 0.80 good cut diamond.

Other considerations, like a huge feather that can affect the resulting stone’s durability, or a big high relief inclusion which can have a huge impact on the Diamond’s clarity grade. Every Diamond are cut to the best economical value that it can provide, if it’s too shallow, it might create this effect called the fish eye effect (Picture Below), if it’s too deep, it might create this effect called the nail head effect (Picture below), both of which are not appealing. Cut is the most important factor in our opinion and should be made priority over the other 4 C’s.

In cost savings, we would recommend a Diamond with Very Good polish instead of excellent as there is not much eye visible difference in these two grades. However, it is important that symmetry and cut are as kept as excellent. A Hearts and Arrow Scope is used very often in retail to show clients the symmetry of the diamond.

Read our Ultimate Diamond Buying Guide which explains how the ASET scope (check light return) and Hearts and Arrow Scope (check symmetry) may be used by some Diamond Jewellers.



Carat weight refers to the weight of a diamond, where 1 carat equals to 0.2 grams. Carat weight does not always determine how big the Diamond appears to our eye, as we mentioned earlier in Cut, a deep cut diamond could look much smaller than the weight it suggests, a shallow cut diamond could look much bigger but when too shallow.

In the current market, due to Diamonds being rarer in bigger sizes, the prices of Diamonds are not linear, which means if a 1 carat diamond is valued at X value, a 2 carat would not be 2X but could be 4X in value. Carat weight is very important when it comes to buying a Diamond, but a beautifully cut and clean 1 carat Diamond will outshine a mediocre cut and included 2 carats Diamond.

There is some truth that a 0.69ct Diamond is cheaper than 0.70ct Diamond even though that is no visible difference and keeping all other aspects constant. This is due to how Diamonds are priced on Rapaport - in weight ranges. However, do note that this is not always true between the specific range 0.99 and 1.00 ct. This is because all Diamond cutters would try to achieve the 1.00 ct weight instead of 0.99, making 0.99 much lesser in the market. A 0.99ct Diamond is usually only made upon a cutter’s mistake. Jewellers would also only stock 1.00 above diamonds instead of exactly 0.99. Hence to satisfy some customers’ request of wanting exactly a 0.99ct Diamond, we have heard of jewellers who would shave away 0.01ct off from a 1.00ct Diamond to achieve the desired weight and send it for regrading at GIA. Unless they specially source from suppliers, this shaving process usually results in a premium for the service and regrading costs, unlike what many consumers would think in terms of cost savings.

Read our Ultimate Diamond Buying Guide which explains more about how Diamond prices are made and each carat price weight comes in a range.


Fluorescence is the glowing effect that a Diamond has when ultra-violet light is shined onto it. The most common colour is blue, while red, green, yellow is uncommon. Unknown to many, fluorescence greatly affects Diamond prices. It is graded from Very Strong, Strong, Medium, Faint, None. Keeping all the other variables contents a None Fluorescence Diamond can be 10-20% more expensive than a Medium Fluorescence Diamond.

Therefore, we see many prices discrepancies in the retail market where some Diamonds seem to be selling at a huge discounted price, because the usually have strong or very strong fluorescence.

Diamonds with medium to very strong fluorescence may show a cloudy milky effect, but this is uncommon and only happens to 10% of the Diamonds in this category. Specifically, blue fluorescence may also make a Diamond (G-H) colour appear less yellow, therefore looking like a (F) colour, as the colours cancelled out each other.

In the resale market, medium to very strong fluorescence is sold for a much lower value compared to Faint or None Fluorescence. In our opinion, if Your Diamond is meant to be kept forever (you won’t sell it or upgrade/exchange it), you can settle for a medium or strong fluorescence, and prioritise other aspects like getting a bigger Diamond instead.

Read our Ultimate Diamond Buying Guide which explains more about how fluorescence affects Diamond Pricings.

Modified Cutting

A round brilliant standard cut has 57 or 58 facets (including the cutlet). Modified cuts have more than these standard number of facets, which would make the Diamond have more scintillations (due to number of surfaces) but it will compromise on the fire (rainbow flashes). There are some jewellers who market their Modified Cut Diamond as the best in the market, having the highest light return etc, but do note that certain cuttings  reduces other important factors such as the fire, hence GIA only gives the standard round cut diamonds a cut grade.

Modified cuts graded at GIA would not be given a grading for cut, only polish and symmetry. In our opinion, buying modified cuts is a thing of personal preference. While most sellers would sell them at a 20-30% premium, it is important to know that these modified cuts in the resale market are worth less in  the resale market like pawnshops compared to a standard cut diamond. This is from our experience working in pawn-shops, knowing how diamond jewellery there is given a price.

The picture belows shows a Solasfera Cut Diamond sold by Singapore Jeweller JannPaul compared to a standard cut round brilliant Diamond. Like I mentioned above, buying modified cut Diamonds is a thing of personal preference. Personally, I prefer facets that are cut in the more proportionate triangle and kite shapes. And as a gemstone dealer who focuses a lot on the investment/resale value, I would always pick standard cuts unless for fancy shapes or fancy coloured diamonds

Read our Ultimate Diamond Buying Guide which explains the major modified cuts in Singapore which shows you exactly what they look like on a grid.



Diamonds can come from many origins, such as India, Africa, Russia, Australia, Canada and much more. There are no differences between Diamonds from each region and thus it is extremely difficult to give an origin report for a Diamond unless it is tracked from mining to end-productions. The most prominent Diamond mines are of course located in Africa, but articles have shown that Russia also have incredible deposits of Diamonds.

In recent years a very special diamond has been found in Russia, it is a Diamond in a Diamond. Named the Matryoshka after its Russian doll-type structure, the double Diamond weighs in at just 0.62 carats.


Diamonds can be treated for its clarity by using methods such as deep boiling, laser drilling or fracture filling. Such diamonds generally trade at much lower prices, but we strongly do not recommend buying such clarity enhanced stones, first for the lack of resell value, and also such stones with so much clarity issues are not as durable.


Synthetic Diamonds are a huge market, possibly the biggest synthetic market of any gemstones in existence. This is not only due to usage of synthetic diamonds in jewellery, but mostly due to extensive use in industrial areas. About 99% of U.S. usage of synthetic Diamonds are industrial, used in areas such as computer chip production, construction, drilling for minerals, natural gas, and oil, amongst much more others.

Synthetic diamonds as jewellery is also trending, even De Beers, one of biggest owners of diamond mines and explorations, set up a synthetic Diamonds venture known as lightbox. Unethical use of synthetic diamonds are also existent, which is mostly for melee stones, mixing the synthetic with natural, cashing in on the fact that most people or even retailers would not check for synthetics as it is a very difficult and costly process to distinguish synthetics from natural diamonds.

From our experience, it is possible to differentiate HPHT (high pressure high temperature) created Diamonds with a loupe as they are oddly cloudy. However, CVD (Carbon Vapour) Diamonds are impossible to differentiate using standard gemological equipment and require advance machinery that only some laboratories can test.

Due to the presence and perfection of these synthetic Diamonds, natural Diamond prices have been falling in recent years. As gemologists with our foundations in gemstone dealing rather than designing, we would therefore always recommend our clients to invest in a rare investment grade coloured gemstone or coloured diamond instead as these kind of stones are actually very rare and would hold value for the years to come.

There also exists many simulants for diamonds, which includes the more famous Moissanites, Cubic Zirconia among others.

Read our Ultimate Diamond Buying Guide which explains more about the simulants and how they have confused consumers in Singapore.


Diamonds are the hardest gemstones in the world. With a Mohs scale rating of 10, Diamond  jewellery of all settings are suitable for everyday wear. Diamonds can be cleaned most of the time in jewellery cleaning machines such as the ultra-sonic machine if they have a high clarity grade. SI Diamonds should not be placed in the ultra-sonic machine for fear of cracking. These Diamonds with bad clarity and many fractures should not be cleaned with jewellery cleaning machines, they should only be cleaned with warm soapy water and a soft brush.

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