What Explains Slightly Included Diamonds?

The slightly included range of diamonds is among the trickier versions in the diamond clarity. They feature a stage before included (I) diamonds are not among the more pricey and higher quality range of diamond clarity grades. However, that does not mean they are a pushover, for, despite their notable shortfalls, the slightly included range of diamonds packs a number of features that new buyers ought to consider.

In this Education page, we will break down the key features of slightly included diamonds, explain the differences between the three sub-grades in this range and what buyers must look for if they are trying to pick a diamond for a jewellery item like an engagement ring.

What are Slightly Included Diamonds?

Slightly included diamonds are one grade above the last group of diamonds that are classified according to clarity. They are separated into three subcategories: SI1, SI2, SI3 with decreasing level of clarity as the numbers increase.

Slightly included grade of diamonds are the starting point for visible inclusions in diamonds. All other diamond grades that sit above tend to mask their inclusions and external blemishes well. Notably under 10x magnification. With slightly included diamonds this is not the case. As inclusions are clearly visible with the aid of such instruments. However, slightly included diamonds also differ from higher clarity grades like Very Slightly Included stones (VS1 and VS2), in that they feature inclusions that upon closer inspection are visible to the naked eye. Notably, those which fall in SI2 and SI3 range.

Slightly included diamonds feature an array of inclusions like clouds, chips, crystals and even slight cavities, in addition to external blemishes. However, what sets them apart from lower-grade stones is the level of visibility and number of these inclusions. For slightly included diamonds if selected carefully make a solid option for more budget-friendly buyers.

What Distinguishes Slightly Included Diamonds?

As a clarity grade that falls into the budget range of diamonds, their main feature is the greater prominence of inclusions that vary in number and degree but are nonetheless a feature in this grade of stones. Notable here are visible defects like clouds, internal chips and knots. However, what is interesting about slightly included (SI) diamonds is that if one is lucky one might be able to find an eye-clean version in this range. Notably, in the SI1 range of slightly included diamonds, these stones can come in a range of different qualities, with respect to clarity, so it is worth shopping around for cost-minded buyers.

Another important point is that Slightly Included diamonds feature a large array of included stones, which means that buyers will have to pay attention not only to the type and number of inclusions but also to where they are placed in the specific stone. For example, a round diamond in slightly included clarity that features inclusions like feathers and needles at the centre might pose a problem in terms of clarity, however, if these are found away from the centre and the specific cut of the stone can mask these inclusions then they might worth a look.

When it comes to the type of inclusions, slightly included diamonds are not the most prominent when it comes to the extent of dents and chips that are a feature of included (I) diamonds. As these are not the severe kind that tends to cause breaks and affect the durability of the stone.

SI1 SI2 and SI3 Diamonds Compared

The slightly included range of diamonds like most other diamond clarity grades is subdivided into three variants: SI1, SI2 and SI3. With each additional number, the quality grade of the stone declines. So SI1 range of stones is better than SI2 and so on. When it comes to factors that distinguish these variants, the first point to consider is that the SI1 range of stones in the slightly included range features gemstones that feature visible inclusions to no visible inclusions.

This is an important difference and budget-conscious buyers who are looking for a diamond that is compatible with a top diamond engagement ring, ought to look out for what is known in the gemstone world as ‘eye-clean’ stones: which feature no inclusions when viewed without magnification. Under 10x magnification however it is a different story.

With SI2 and SI3 diamonds, things are a lot different. With neither of these clarity grades have diamonds without visible inclusions, in addition to featuring a higher number of them. When opting for SI2 diamond clarity stones it might be wise to choose diamonds which feature inclusions and other shortfalls that are away from the centre stone. This might enable the buyer to carefully mask these inclusions with the right ring setting. Thus engagement ring styles that can cover a portion of the centre stone might be worth considering.

Another important factor is the price. SI1 and SI2 diamonds do feature a somewhat significant difference (often over $1000 per carat for a very good Round cut diamond) when it comes to pricing and especially when it comes to SI1 and SI3 diamonds. Thus SI2 diamonds with some inclusions are a good buy provided you are going for a stone with a solid cut, such as a round cut diamond.

Slightly Included Diamond Engagement Rings

Getting to the business end of things, the question is: should you opt for slightly included diamonds for your engagement rings? The answer is that it depends. First off, slightly included diamonds are a solid budget option stone, and when controlling for factors like the colour (preferably in the F – I range) and cut (Round, Cushion and Princess Cuts preferably) the buyer might be in for a solid choice. Especially if they are opting for a larger stone.

A word of advice for buyers who may consider SI2 and even SI3 grade diamonds, some of these stones tend to feature inclusions which are spread out. Giving a distinct ‘salt and pepper’ look, that some gemstone buyers might prefer. Others however are advised to stick to the SI1 range of stones for their diamond engagement rings.