Monthly Archives: May 2014

The 4 C’s of Diamond Buying

4 cs editedThe 4 C’s of Diamond Buying


Diamonds are valued by how close 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 quality Jewellers 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..

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.

Our tip: Sacrifice a bit of size for a better colour 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.

Our 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 – look for diamonds SI2 grade or higher.


Of all the 4Cs, cut has the greatest effect on a diamond’s beauty and quality.   The more precise the cut, the more captivating the diamond is to the eye.  The cut of a diamond greatly impacts a diamond’s brilliance; this means if it is cut poorly, it will be less luminous.



A carat is the physical weight of the diamond measured in metric carats. One carat equals 1/5 gram and is subdivided into 100 points. Carat weight is the most objective of the 4Cs.


And there is actually a 5th C……


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 should this effect your purchasing decision?

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 Trade Me 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.

Round brilliant polished diamonds.



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Birthstone of the Month May – The Emerald


Emerald 2The Emerald is the sacred stone of the goddess Venus. It was thought to preserve love. It has long been the symbol of hope and is  said to bring the wearer reason and wisdom.
A favourite of Royalty and Celebrities alike.  If you are lucky enough to have a birthday in May – then this is your Birthstone. ………… 

The namecomes from the old French word ‘esmeralde’, which was derived from the Greek word ‘smaragdos’ meaning ‘green stone’. By definition, Emerald is any medium to dark green beryl coloured by chromium. Green beryl coloured only by vanadium is not considered to be true emerald, but rather as simply green beryl. Since the 1960s, the American jewellery industry changed the definition to include vanadium coloured beryl as ‘Emerald’, but in the UK and Europe, they are still not recognized as such. The historical green colour of Emerald is unparalleled in the world of gemstones and it is considered as one of the most ‘precious four’ of all gemstones, which also includes Sapphire, Ruby and Diamond. Although Emeralds are one of the most valuable gemstones available today, most are very heavily included, rendering their resistance to breakage as generally poor.
Though Colombia is the most the most famous source for ‘deep green’ Emeralds, Emerald deposits are mined from many locations around the world. Recent decades have seen Emerald production increase as a result of newly discovered deposits in South America, Africa and across Europe. Today, Brazil and Zambia are now some of the leading producers of fine Emeralds, following Colombia. Brazilian Emeralds are prized for their excellent clarity and slightly yellowish green colour, while Zambian Emeralds are desired for their slightly bluish green colour, which is similar to that of Colombia’s ’emerald-green’ Emeralds.

Almost all natural Emeralds contain distinct characteristic inclusions and almost all are treated with oil or resin to fill tiny fissures and cracks. It is the presence of these flaws and oil which makes it quite easy to identify and distinguish natural Emeralds amongst other similar gemstones. Artificial light will expose and amplify inclusions and fractures that prove the stone to be a natural Emerald. Emerald colour is owed to trace amounts of chromium and vanadium, and colour is best admired under natural daylight. One of the easiest methods to identify green Emeralds is to test for specific gravity (density) and hardness. Like all forms of Beryl, Emerald is harder than Apatite, Quartz and Feldspar, but is slightly softer than Spinel, Topaz and Sapphire. However, they are generally more fragile than other Beryl’s, owing to their naturally included state.
We have a range of beautiful Emerald Jewellery in store at Global Diamonds and have unset stones available to be able to create the design to match your style.




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