Diamond Clarity

Description

If you buy an uncertified diamond, one of the first tests you may want to do is to check that the stone is real and natural and whether it has been artifically treated in any way. This video shows the process and equipment used by diamond grading laboratories to check each diamond.

Video Transcript

It is possible to test the diamond using an electronic diamond tester. To be 100% accurate though, you will need to send the stone to a laboratory where it can be tested in greater detail.

The grading laboratories use a piece of equipment developed by DeBeers which is called Diamond View. This instrument makes visible the growth structure of the diamond. The growth structure is very different between natural diamond and synthetic diamond or other types of stone. In nature, there is a continuous growth and dissolution of the diamond which gives an irregular growth pattern.

This is in contrast to what you see in a synthetic diamond which is growing in a systematic and continuous way. A diamond can also be treated to try to enhance its appearance. For example, a diamond can be heated, in order to improve its apparent colour, or it can be drilled with a laser and backfilled with glass to improve the apparent clarity grade.

To check if that has happened the laboratories use a technique called spectroscopy. This involves shining a light at the diamond at an atomic level and looking for the interaction and the light and diamond. A trained person can assess the reading to see if any ‘enhancements’ have been applied to the diamond.

When you look at a diamond certificate, you will often have a clarity characteristics line or an inclusion map with a key. This is telling you what the inclusions look like in your diamond and in the case of the inclusions map, where they are positioned within the stone.

We can explore the different types of inclusions, including crystals, needles, feathers, and naturals. The first type of inclusion to consider is called a crystal. Some crystals can resemble a diamond within a diamond, and some can resemble bubbles. Some crystals can be so thick that they start to take on a darker and even a black appearance.

A common inclusion type is called a cloud. This is a very broad term, as it means there is a collection of small inclusions close together. They can look, though, very different. If the diamond has a larger cloud, it may start to appear foggy or hazy, and this can have a significant effect on the appearance of the stone to the naked eye.

A feather is probably the easiest type of inclusion to identify and to find. A feather is a crack or a fracture within the stone that has the appearance of a feather. These are caused by immense pressure as a diamond has risen through the earth's crust. They are nearly always white, and they vary significantly in size and shape.

Needle inclusion: this is similar to the crystal inclusion, but as the name suggests, it is needle-like in shape. This type of inclusion is often white, and is very rarely visible to the naked eye.

An indented natural is where part of the skin of the rough diamond is left on the surface of the polished stone and that then intrudes into the diamond.

There are some other less common types of inclusions, such as twinning wisps. These are formed when a diamond stops growing and then starts growing again, maybe thousands of years later, but in a different direction. This change in grain leaves a mark in the stone, rather like the crown in your hair or a knot in a piece of wood.

Description

Every GIA graded diamond has a clarity grade - however, these grades can be quite broad. At Samara James, we hand-pick diamonds which are towards the the top of each grade of clarity, rather than the middle or bottom. In this video we show why this is important.

Video Transcript

By definition, every single diamond is completely unique. This is why two diamonds, that may sound the same on paper, can look completely different in real life. One of the factors that makes a diamond unique is the clarity of the stone and, in particular, the nature and position of the impurities or inclusions.

Every diamond has different types of inclusions, formed over billions of years. If you take a particular grade of clarity, for example SI2, you would find a range of diverse appearances from good to bad.

If you select a particularly nice SI2 clarity diamond, there will be some inclusions visible under magnification, but these are not visible to the naked eye. But if you select a lower quality SI2, then the inclusions will be much more prominent and will be visible to the naked eye.

Diamonds which have the same level of clarity will often be priced very differently, even though they are the same GIA clarity grade. Thus, prices for individual diamonds on the Internet can vary considerably, even if the certificate information appears identical.

Clarity grades are assessed at ten times magnification. The highest clarity grade is flawless, and this means there are no impurities in the diamond visible at ten times magnification.

VVS1 and VVS2 is the next grade. VVS stands for very very small, and at this level the impurities will resemble five to ten microscopic specks of dust within the stone. This level of clarity is very rare, and you certainly can not see the impurities with the naked eye.

After VVS on the scale is VS1 and VS2, where VS stands for very small. At this level the size and the quantity of inclusions are getting more frequent, although they are still not visible to the naked eye in a round brilliant cut.

Below VS is SI1 and SI2. SI stands for small inclusions. This is the level where the inclusions are getting quite a lot larger and more obvious, and then can sometimes be seen with the naked eye. In fact, in general around 30% to 40% of the inclusions of an SI2 clarity diamond are visible.

There are quite a lot of differences between individual diamonds which are graded at this level. It is therefore important to check the diamond from the side, because often the inclusion from above may be obscured by the facets in the crown, whereas from the side the inclusion could be easily visible. At Samara James, we only sell diamonds which we have checked are 'eye clean'.

Beyond SI2 are the levels known as I1, I2, and I3. These diamonds do have obvious flaws when viewed carefully and are considered typical commercial quality. This means that most of the uncertified diamonds that, for example, you might find on the High Street will often be somewhere between a I1 and I2 level.

We look under various lighting conditions to make an optical assessment of the fire, scintillation, brightness and contrast of the diamond. We also then assess the lustre of the diamond to check how well the light reflects off the facets and also whether the diamond has any milkiness.

For round diamond we check the quality of the Hearts and Arrows pattern, ensuring the diamond has perfect optical symmetry to give the best light return. Fancy shaped stones, like princess cut, are checked to make sure they are the right shape and proportions.

We then put it in a white tray to check the colour of the stone and see if the diamond has any colour overtones. Stones can have green or brown tinges depending upon their country of origin and this characteristic isn’t graded by GIA.

Lastly we check the documentation and provenance of the diamond. This is to ensure not only every diamond that we offer complies with the Kimberley process, but that we know the exact details of the supply chain of the diamond, so we can guarantee every diamond passes our ethical and quality standards. You can buy with confidence knowing that our diamond experts have checked every detail of the diamond to ensure it will match the highest of expectations.

Description

Whether you are looking to learn a bit more about diamonds or you would like to become more of an expert, our diamond videos and diamond guides are made just for you. In this video, we explain 'diamond cut' and why it is so important to how beautiful the diamond looks.

Video Transcript

In some cases, a diamond can be made too shallow. Again this means that the angles are less than optimal, so light leaks through the bottom of the stone. A round brilliant diamond is given a cut grade by the major grading labs like GIA, IGI and HRD. These grades are Poor, Fair, Good, Very Good, Excellent.

The cut grade gives you a good starting point guide but it is worth knowing that each grade involves a range of quality, so two diamonds which for example are both Excellent Cut will often have differing levels of optical performance.

Here is a comparison between a GIA "good cut" and one of our Hearts and Arrows diamonds which has been graded Excellent cut by GIA. You are looking to see which stone has more flashes of refracted colour as it moves through the light - this is what you will see when you view the diamond in direct sunlight or office lighting.

Comparing the brightness of the two diamonds, the hearts and arrows has a lot more white light return and so looks the brighter diamond with better contrast pattern. The differences you are seeing are down to the quality of cut of the stone. When you are choosing a diamond, if you want it to be a beautiful as possible, it is important to choose the very cut possible.