Chilton’s Antiques: Quick read, how to buying a diamond

Diamond, Cubic Zirconia, Moissanite – Which is Right?

As we know in today’s society diamonds are a girl’s best friend, but what do we know about them? Since diamonds were first discovered in India 3,000 years ago, they have been put to many uses. They have been used in trade and barter, for healing properties, used for magic and adornment and even in industry. What makes a diamond so unique is not only its beauty but its properties which are unrivalled by any other natural material for its scarcity, abrasion resistance, value, resistance to chemical attack and hardness.

In this post, we’ll go through the properties of diamonds, what they are, what they mean and how to get the most from your buying experience. Unlike most high-value purchases, like homes and cars, diamonds will stay with you for life. You’ll look at them every day, experience with them and they’ll become a part of your life. This culminates as one important buying decision!

A Short History of Diamonds

In Africa in the 1870s there was a diamond rush after a young South African boy a few years earlier, had discovered a transparent rock on his father’s farm.

Over the next fifteen years, South Africa yielded more diamonds than India had in over 2000 years. India prior to this discovery was the major supplier of diamonds.

South Africa was a land of opportunity, Cecil John Rhodes, at age 17, followed his brother to South Africa. There he became a business entrepreneur and eventually bought up many diamond claims and then finally went on to form De Beers Consolidated Mines.

More often than not, diamonds were sourced to be incorporated into Engagement Rings. Engagement Rings have existed since the third millennium BC in almost all cultures. They were made from all types of material from gold to wire.

In 1477, the first engagement ring appears to have been given by Emperor Maximillian I of Austria. It was perceived in these times that the diamond would reflect the light and warn off any evil forces sent out to destroy the couple.

Engagement rings were presented on this romantic occasion as a promise and a pledge to confirm the arrangement of future marriage. The ring was displayed for all to see as it meant that the lady was no longer available.

Diamond Treatments

Currently, there are treatments that diamonds are subjected to in order to make them appear more valuable than they are. A lot of these treatments are unstable and unpredictable making them less desirable then untreated diamond. Fortunately, Chilton’s Antiques only deal in untreated diamonds.

Clarity enhancement

  • Laser Drilling
  • Fracture filling

Colour enhancement

  • Irradiation
  • Coatings
  • High-pressure, high-temperature treatments

With advancing technology, much has been done to try to improve near gem-quality diamonds to make them more commercially viable. This is achieved by taking a poor-quality diamond and enhancing its clarity by filling its fractures from within.

The procedure entails forcing a colourless substance into the fractures to hide them. This treatment is not stable and if a diamond is subjected to heat the liquid can dry up and the stone reverts to normal with all its original faults.

Causes of this aren’t extreme and can be as simple as sitting too close to a heater, washing up in hot water and even taking your rings to be cleaned or resized at an unaware jeweller.

The Four C’s

During a surplus of diamonds in the 1930s and the realisation that more could be asked for certain quality stones, a process was introduced to grade the stones. This process sorted out desirable diamonds from the rest, unlike any other gemstone. This process graded the Cut, the Colour, the Clarity and the Carat (or size).

Alongside this new process, De Beers hired a marketing manager that came up with the marketing slogans still heard today; “Diamonds are forever”, “Diamonds are a girl’s best friend” and “A month’s salary for a lifetime of love.


How the diamond is cut and presented plays a vital part in its fire and brilliance. Cutting a diamond too shallow and light is lost from the bottom of the stone, causing the diamond to lose its brilliance. Cutting the stone too deep and the light will escape from the sides resulting in the stone having a dark and dull appearance.

Badly cut stones may be disguised by numbers and percentages in Valuation Certificates. The average consumer could easily misinterpret the implications and choose an inferior cut stone.

The ideal percentages are all different they depend on the stone’s shape which will determine its fire and its brilliance. The best way to work out whether a diamond is well cut is to be able to hold it near a light and make sure it looks bright. Of course, the best options is to seek advice from professionally trained and certified gemologists and diamond graders such as Chilton’s Antiques.

Rose Cut – Rose cuts were invented in the mid-16th century, it was also known as the Antwerp rose, Crowned Rose Cut, Dutch Cut, and the Full Holland Cut. The Rose cut forms a single hemisphere for a total of 24 facets or it can be two back-to-back hemispheres (Double Dutch Rose) forming a total of 48 facets. This cut was also often foiled from behind to create more dispersion. 

Old Mine Cut – the 1700s – The Old Mine cut is the earliest form of the “brilliant cut” diamond. Basically, a square with gently rounded corners and “brilliant” style facets. The crown is typically tall, resulting in a smaller table. The culet cut off leaving an eye effect (hole in the middle) that is visible when looking down into the stone from the table.

Old European Cut – 1800s – The Old European cut was the prototype of the modern Brilliant Cut. The Old European diamond cut has a very small table, a heavy crown, and very tall overall depth. Like the modern round brilliant, the old European diamond has a circular girdle.

The Modern Round Brilliant Cut – The Modern Round Brilliant Cut diamond was developed by Belgian diamond-cutter Marcel Tolkowsky in 1919. This cut is also known as the Tolkowsky Cut and Tolkowsky Brilliant.

Even with modern techniques, the cutting and polishing of a diamond resulted in a loss of as much as 50% of the stone’s total weight. The round brilliant cut was a partial solution to this problem. This Modern Round Brilliant Cut Diamond came into prevalence between the 1950s-1960s when technology advancements had improved.


Diamonds come in a wide range of colours. The main scale is the colourless scale D-Z. Diamonds are graded on this scale from colourless to yellow with a letter from the alphabet allotted to each colour grade.

The colour scale starts at D and devolves through to Z. Any colour lower than Z is termed fancy diamond and the price begins to soar again due to their rarity. The most expensive diamonds in this series are colourless stones. The less colour in a diamond, the whiter light can pass effortlessly through and be dispersed as rainbows of colour on top.

Whilst forming, the nitrogen in the earth and make up causes the yellowness in stones. Obviously, there are many yellow stones on the market, and this makes the white stones highly sought after and maintains their price because they are rarer.

Australia produces 40 million carats per year: 52% for industrial use (saw blade tips, cutting devices etc.) and 40% is near gem quality, with only 5% actual gem-quality. In the current market, most of the so-called bargain diamonds found on the internet and in shopping centre chain stores are of industrial quality.

When choosing a diamond Chilton’s Antiques recommends you look no lower than H-I grading. Also, remember that not all diamonds are correctly graded! Many certificates display incorrect grading from careless or non-qualified retailers.


The observation of internal features and faults in diamonds for commercial purposes began at the beginning of the 20th century in Paris. Paris, at the time, was the trade centre for the world’s diamonds.

In the 1930s the GIA bought in the first quality grading system. A perfectly clear diamond which is free from inclusions is a very rare find. Most diamonds contain very tiny inclusions that, like fingerprints, make each diamond unique and identifiable.

Diamonds can really have their own ‘DNA’ (characteristic set of markings), Mother Nature’s fingerprint. The fewer the inclusions, the more the diamond will sparkle. A diamond’s clarity can only be determined by using an x10 magnification and a trained eye.

Letters are used to denote clarity grades: FL, IF indicate a flawless or internally flawless diamond or LC (loop clean); VVS means very, very small inclusions that are not visible to the naked eye.

These can be 1 or 2 type inclusions; VS simply means very small inclusions, again not visible to the naked eye; SI means small inclusions and I or PK means that inclusions can be detected by the naked eye and indicate a poorer quality diamond.

When choosing a diamond, Chilton’s Antiques recommends you look for grading between VS and SI clarity.


Carat refers to the weight of the diamond. One carat is divided into 100 points and generally, if a client wants a larger size diamond, they sacrifice some clarity and colour to achieve size.

If you want the best of the 4 C’s be prepared to pay a premium for this. There is no substitute for quality.

There is plenty to think about before buying a diamond ring and the best advice that can be given to anyone buying a diamond is to do just that – get the best advice. Go to someone who is knowledgeable, trained and reputable and who is prepared to take the time to explain the diamond you are buying.

Unlike many other large purchases like cars or even houses diamonds are usually kept for the lifetime of the wearer because of their sentimental value and are looked at every day by the wearer, so getting it right is important.

Chilton’s Antiques is well known for our range, ability to source stones, variety of styles and quality of service to customers. In addition, we have registered Valuers and Diamond Graders in the store at all times to advise you on your diamond selection.

Imitation Diamonds: Synthetic diamonds, Cubic Zirconia and Moissanite

Synthetic diamonds are stones that are grown in highly controlled laboratory environments using advanced technological processes that duplicate the conditions under which diamonds naturally develop. Synthetic or man-made diamonds consist of actual carbon atoms arranged in the characteristic diamond crystal structure, so they have the same molecular structure as their natural counterparts.

Since they are made of the same material as natural diamonds, they exhibit the same optical and chemical properties. These stones will look identical to a natural diamond, the only difference being one is made artificially, and one is made in the earth naturally.

It is important to note the major differences between laboratory-grown diamonds and diamond simulants. Diamond simulants, such as Cubic Zirconia and Moissanite, look similar to diamonds but are not true copies.

Natural and laboratory-grown diamonds have thermal conductivity properties that differentiate them from Cubic Zirconia with a handheld diamond tester.

Some laboratory diamonds, along with some natural coloured diamonds, may be mistakenly identified as Moissanites when using certain diamond testers due to similarity in their electrical conductivity. Trained gemologists can typically distinguish between diamond and Moissanite due to their differing refractive properties, with Moissanites being double refractive and diamonds being single refractive.


The mineral Moissanite was first discovered by a scientist Henri Moissan while examining rock samples in a meteor in 1893 in Arizona. At the time he thought they were diamonds but later he re-identified them as silicon carbide.

Moissanite was introduced into jewellery market in 1998 after C3 INC, Charles and Colvard were granted a patent to re-create and market laboratory grown silicon carbide crystals.

Charles and Colvard marketed Moissanite as a lower-priced alternative to a diamond. These stones are of better quality than Cubic Zirconia as they wear better. The only difference between Moissanite and CZ is that Moissanite has a stronger colour dispersion, you can see more of a rainbow colour through the stones.

They are unnaturally bright so they can look somewhat slightly fake and they are double refractive with a mirror effect inside the stone. Many clients have used them as a temporary stone, which they can afford now but will replace at a later time. They last longer and look better than a CZ with wear and tear.

Depending on the age of the Moissanite and which generation stage it is from, as with time the company has developed better technology and is now able to create whiter looking stones. When Moissanite first came out on the market the colours range was I-K with a definite yellow tint- the new generation of Moissanites are much whiter E-F -G colour ranges.

Cubic Zirconia

Cubic Zirconia (also known as CZ) is similar looking to a diamond with its brilliance and crystal clarity, but it is a synthesized (man-made) crystalline material that is colourless, hard, and flawless.

Cubic Zirconia started being produced in the 1970s because of its diamond-like qualities, very low cost, and overall durability.

Cubic Zirconia crystals are made by melting powdered zirconium and zirconium dioxide together in a laboratory and heating them up to 4,982ºF. A Cubic Zirconia is a perfectly man-made, flawless-looking stone.

There are some ways to distinguish Cubic Zirconia from a diamond as follows:

  • Thermal conductivity – Diamonds are thermal conductors while Cubic Zirconia is a thermal insulator. This is what makes the diamond stand out next to the Cubic Zirconia with special diamond testing machines
  • Hardness –Diamond has a rating of 10 and Cubic Zirconia has an 8 on the Mohs hardness scale. With time CZ do scratch and have parcel wear over the top of the stone
  • Density – Cubic Zirconia is 1.7 times denser than a diamond. Often powder remanence is seen as small cloud particles. Other batches are better well-formed and flawless
  • Refractive index – Diamond has a refractive index of 2.42 vs. Cubic Zirconia has an index of 2.15-2.18
  • Cut – Diamonds are typically cut differently than Cubic Zirconia gemstones, due to cost. The time spent cutting a CZ is not as cost-effective as cutting on a diamond. The old saying you get what you pay for applies here
  • Dispersion – Diamond 0.044 vs. Cubic Zirconia 0.058-0.066
  • Colour – Cubic Zirconia is equivalent to the perfect “D” on a diamond’s grading scale, but it also comes in other colours as well

My final thoughts as a Diamond Grader, Registered Valuer and a woman, is that there simply is no substitute for a natural diamond. You will always know yourself it is fake; it is like owning a fake designer handbag.

A woman deep down knows the difference. I feel that there is a marketplace for Moissanite and Cubic Zirconia as they are priced accordingly and are usually worn as fun dress jewellery.

I feel the price difference for synthetic stones is too high, they are not good value for money. Synthetic diamonds will never keep their value when comparing them to natural diamonds; that is why at Chilton’s Antiques we do not sell synthetic diamonds and never will. We also personally guarantee that we buy Non-conflict Diamonds.

579 Kingsway
Miranda, NSW 2228


About Elizabeth Stevens

As the Principal of Chilton's Antiques and with close to 30-years experience in the industry, CINOA, AAADA and NCJV noted expert, Liz Stevens is a consummate professional. Lecturing and writing papers on Gemology and Antique pieces internationally, as well as hosting a 7-year running Antiques Radio Show on 2UE.