Buying A Diamond Ring


Chilton's Antiques history of diamonds

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. Some were simple; others were set with jewels of all descriptions. Rings were chosen to commemorate a variety of occasions, including friendship, love or sorrow. Rings have indeed played a significant role in relationships and are part of our social history.

Engagement rings were presented on this romantic occasion as a promise and a pledge to confirm the arrangement of the future marriage. The ring was displayed for all to see as it meant that the lady was no longer available. Chilton's Antiques sells a wide range of antique engagement rings, many with diamonds or diamonds & other stones.

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.

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

Diamond with red ribbon

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. Did you know that no other stone has been graded like diamonds? When you buy a diamond you look for the 4C's- CUT, COLOUR, CLARITY, and CARAT (or size).

This process was first introduced in the 1930's as there was a surplus of diamonds and it was realised that more money could be asked for certain stones. Until this point in time, diamonds were really just priced on their size.

At the same time De Beers also hired a marketing manager that came up with the marketing slogans that we still hear today such as "diamonds are forever", "Diamonds are a girl's best friend" or  "A month's salary for a life time of love".


The chemical composition of diamonds is Carbon and they have the highest thermal conductivity of any mineral. The fact that they are also very strong makes them the most sought after mineral. There are 5 different types of diamonds and they are mined using two different methods.

Alluvial- where they are dredged up from the ocean floors as in the South African coastline.

Primary- such as Kimberly Argyle mine in Western Australia.

The discovery of the African diamond deposits in 1867-1871 was the single most important event to influence the development of a grading system. With the increasing quantity of diamonds hitting world markets, their rarity and value was diminishing therefore a criteria was set up for: colour, cut & then inclusions (clarity).

Diamond before being cut Diamond before being cut

Diamond crystal in rock- their natural form


Currently there are treatments that are done to diamonds to make them appear more valuable then they are. You can buy with confidence at Chilton's Antiques as we only sell untreated diamonds. A lot of these treatments are unstable & unpredictable making them less desirable then untreated diamond.

These treatments are

  1. Clarity enhancement

    * Laser Drilling
    * Fracture filling

  2. Colour enhancement

    * Irradiation
    * Coatings
    * High pressure high temperature treatments.

In the current field of new age 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, for instance a PK clarity grading 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 back to normal with all its original faults. This includes sitting too close to a heater, washing up in hot water and even taking your rings to be cleaned or resized at a jewellers.

Diamond with colour enhancement

Most Jewellers are not gemmologists or diamond graders so their knowledge is limited to the making, designing and repairing of jewellery. They do not have an in depth understanding of stones and rely solely on what the wholesalers tell them, which can be a gamble.

The diamond treatment process can be identified visually by turning the stone in certain angles so that light bounces off the filling and flashes of purple or orange as can be seen in the photo. This of course is not seen in untreated diamonds.


Diamond laser drilling

Another form of diamond treatments that is currently on the market is laser drilling. This is done by using a laser to drill down into a mineral inclusion and filling it up with acid that dissolves the mineral inclusion. The diamond is not affected by this, only the inclusion which is susceptible to the acid. This treatment can "improve" the diamond by ½ to full grade i.e. taking a PK stone with a visible inclusion to a grade of SI, small inclusion. Then there is a drill hole left by the laser, this can be left as an empty void or be filled up with glass. Diamonds that are treated with the glass filling have a lower melting point and cannot be exposed to heat such as any repair work that needs to be carried out, washing up in extremely hot water or even sitting too close to a heater can cause the glass filling to come out. If left unfilled by glass, dirt and dust can fill up the void making it look very dirty and impossible to clean, also leaving it susceptible to cleaving (knocking or bumping it can spilt in half). The drill hole can be seen under a microscope by a trained professional diamond grader as seen in the photo above.

At Chilton's we protect you against this by having our diamond graders check all stones, regardless of what is stated on accompanying certificates.

The four C's for diamonds are the main features to be aware of and discussed when buying your ring.


Different types of diamond cuts


Too shallow: Light is lost out the bottom causing the diamond to lose its brilliance.

Too Deep: Light escapes out the sides causing the diamond to become very dark and dull in appearance.



Diamond proportion analysis

Given the example of two stones both of the same colour, clarity & size, one of which has a lot of sparkle and is better able to handle light, the other being badly cut with all the wrong proportions, which diamond would you want? Badly cut stones may be disguised by numbers and percentages in Valuation Certificates. The average person 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 light and make sure it look bright or to seek advice from professional diamond dealers such as Chilton's, where we take all the worry and stress out of buying a diamond.


Development though the ages of the diamond cutting technology.

Antique diamond cuts

Diamond antique cuts

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.

Diamond rose cut

Old Mine Cut - 1700s

The "old mine" cut is the earliest form of the "brilliant cut" diamond.

This Old Mine cut is basically 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.

Diamond old mine cut 1700s

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.

Diamond old european cut 1800s

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 1950's- 1960's when technology advancements had improved.

Diamond modern round brilliant cut


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 descends to Z. Lower than Z in colour is termed fancy diamond & 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 more white light can pass effortlessly through and be dispersed as rainbows of colour on top.

Diamonds in different colours

What causes the yellow colour in diamonds? Nitrogen in the earth causes that yellowness in the 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 today unfortunately most of the so called "bargain" diamonds found on the internet and in the chain "low cost stores" are of industrial quality.

When choosing a diamond Chilton's 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 people.

Diamond colour grading


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 centre for the trade in diamonds. In the 1930's 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 there own ‘DNA' (characteristic set of markings), Mother Nature's finger print. 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. Diamonds are only put into these sub grades of 1 & 2 over the size of 0.40cts.

Chilton's recommends the grading from VS to SI Clarity.

Diamond clarity chart


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 is well known for its range, ability to source stones, variety of styles and quality of service to customers and has registered Valuers and Diamond Graders in the store at all times to advise you on your diamond selection.

Determining carat in diamonds


Diamonds now come in a wide variety of shapes for you to choose from:

Choice of diamond shapes

We can design settings to accommodate any shape or size that you desire.


At Chilton's Antiques at Miranda we make it our business to know about diamonds and to make sure our customers are well informed about their diamond purchase. We have a registered valuer in the store- Liz Stevens, who is a skilled Diamond Technician and Diamond Grader, is happy to share her skills and knowledge with all customers, when making such an important purchase as a diamond engagement ring or dress ring. Examinations and grading of the diamonds is done in our store and all diamonds purchased come with a qualified valuer's certificate from a NJVC (National Jewellery Valuers Council) Valuer so you know that the diamond you buy is exactly what you are paying for. If you have any further questions about diamonds, visit us instore or give us a call on (02) 9254 0630

We also personally guarantee that we buy "Non conflict Diamonds" so you can rest assured that your diamond does not have an immoral criminal past.

Elizabeth Stevens

Fellow of the Gemmological Association of Australia (FGAA) National Jewellery Valuers Council (NJVC) Accredited Valuer Member of the CINOA Federation (Confédération Internationale des Négociants en Oeuveres d'Art) Member of the AAADA Antique & Art Dealers Association Gemmologist * Diamond Grader * Diploma of Diamond Technology