SI2 Clarity Diamonds: What the Grade Means and When It Works

What does SI2 clarity mean?

Clarity is one of the four Cs of diamond grading, and it describes the tiny internal features (inclusions) and surface marks (blemishes) that almost every diamond has. SI stands for Slightly Included, and SI2 is the lower of the two SI grades.

GIA defines the SI grades as having inclusions that are noticeable to a skilled grader under 10× magnification. The grader looks through a loupe (a small 10-power magnifying lens) or a microscope at that power, and the grade is based on what they see, not on what you see with the naked eye. At SI1 the inclusions are noticeable; at SI2 they are easier to find, larger, more numerous or better placed to be seen.

On the full clarity scale from FL to I3, SI2 is the eighth of eleven grades: FL, IF, VVS1, VVS2, VS1, VS2, SI1, SI2, I1, I2, I3. At the top are flawless and internally flawless stones, where a grader finds nothing inside at 10×. Below SI2 are the I (Included) grades, where inclusions are obvious and can affect brilliance or durability.

You may also see SI3 on some older reports. It was used by a few labs for stones between SI2 and I1, but GIA and IGI do not use it. If a term like this is unfamiliar, our jewellery glossary explains each one.

Are SI2 clarity diamonds eye-clean?

Some are, many are not. Eye-clean means you cannot see any inclusion when you look at the diamond face-up, at a normal viewing distance of about 25–30 cm, without magnification. It is not a grade on the report; it is a judgement you or your jeweller make by looking at the stone.

At VS2, the grade where most stones become eye-clean, the large majority of well-cut brilliants pass that test. At SI1 most still do. At SI2 it becomes a stone-by-stone question: the inclusions are big enough that their size, colour and position decide whether you notice them.

Photos and videos are taken under magnification and strong light, so they make inclusions look worse than they are. A high-resolution video at 10–20× will show every SI2 inclusion clearly; that does not mean you will see it on the hand. The opposite also applies: a stone that looks clean in a small, low-quality photo may not be.

What inclusions do SI2 diamonds have?

The type of inclusion matters as much as the grade. Two SI2 stones can look completely different: one with a small white crystal under a side facet, one with a black crystal under the table. These are the inclusions you will see most often at this grade:

Two report details are worth reading closely. The plot (the diagram of the stone with inclusions marked in red and green) shows where each one sits. And if a GIA report says "Clarity grade is based on clouds that are not shown", the main inclusion is a cloud. Ask for a video before you go further, because haze is the hardest SI2 problem to see in a photo.

Lower-clarity stones are also the most likely to have been treated to look cleaner. Read about laser drilling and fracture filling before you buy an SI2 that seems too cheap. GIA grades laser-drilled diamonds and notes the treatment, but it does not grade fracture-filled diamonds. Treatment is far more routine in coloured gems such as emeralds, which are routinely oiled, than in diamond, where it should always be disclosed.

Which diamond shapes hide SI2 inclusions best?

Facet style makes the biggest difference. Brilliant cuts have many small triangular and kite-shaped facets that break light into flashes, and those flashes camouflage inclusions. Step cuts have long, flat, parallel facets like a staircase, with a large open table that works like a window into the stone.

Pear, marquise and heart shapes have a fragile point, and princess cuts have sharp corners. A feather close to any of these is a durability risk as well as a visual one, so read the plot carefully. For step cuts, our guide to clarity for Asscher cuts explains why the bar is set higher.

Does carat size or metal colour change how SI2 looks?

Size matters a lot. Clarity is graded relative to the stone, but a bigger diamond has a bigger table and bigger inclusions in absolute terms, so they are easier to see. Under about 1 carat, finding an eye-clean SI2 round is realistic. From about 1.5 carats up, the search gets harder, and from 2 carats many buyers find SI1 or VS2 a safer starting point.

Metal colour has a smaller effect. Yellow and rose gold reflect warm tones into the stone, which can soften the look of white feathers and clouds slightly, but they will not hide a black crystal. White gold and platinum are neutral and show the stone as it is. Metal colour matters far more for diamond colour than for clarity; our guide to whether to spend on colour or clarity covers that trade-off.

The setting can help. An inclusion near the girdle can sit under a claw. A bezel covers the whole edge. A halo draws the eye outward and makes small marks in the centre stone harder to notice. What a setting cannot do is hide an inclusion under the table, so never count on it for that.

How much do SI2 clarity diamonds cost in Australia?

SI2 is usually the lowest clarity grade where many buyers still expect an eye-clean stone, and that is why it is such a strong value grade. The price steps below are approximate ranges for a natural 1.00 carat round brilliant, G colour, Excellent cut, in AUD. Real prices move with the market, the exact stone and the lab report.

The steps get larger as you climb. Moving from SI2 to SI1 costs a modest amount; moving into VS1 diamonds, VVS2 or VVS1 stones costs much more, for differences you can only see under magnification. Our page on whether VVS clarity earns its premium works through that question.

SI2 vs SI1 vs I1: what is the difference?

SI2 versus SI1 is the most common decision at this end of the scale. An SI1 gives you a wider choice of eye-clean stones; an SI2 gives you a lower price if you are prepared to look at more of them. Below SI2, the included grades, I1 to I3 can still be eye-clean in rare cases, but most show inclusions face-up, and some carry durability risks that a setting cannot fix.

Should you choose a lab-grown SI2 diamond?

SI2 is far more common in natural diamonds than in laboratory-grown ones. Most lab-grown stones on the market are graded VS or better, because growers can produce clean crystals routinely and cutters tend to choose the cleanest material. Read what clarity is typical in lab-grown stones for the detail, including the metallic inclusions of HPHT growth and the dark pinpoints sometimes seen in CVD stones.

Because lab-grown diamonds already cost much less than natural, the price gap between a lab-grown SI2 and a lab-grown VS2 is small in dollar terms, often a few hundred dollars at 1 carat. For most lab-grown buyers, stepping up to VS2 or VS1 makes more sense than saving at SI2. For natural diamonds, where the step is much larger, SI2 is where the grade earns its place. Both natural and lab-grown stones should come with an independent report from a lab such as GIA or IGI.

When is SI2 the smart pick, and how do you choose one?

SI2 makes sense when you want a natural diamond, you prefer a brilliant shape, the stone is roughly 1 carat or under, and you would rather put your budget into size, cut or colour than into clarity you cannot see. It is a poor fit for step cuts, very large stones, and for buyers who know they will always look closely. Use our colour and clarity pairings for each shape to match the grade to your shape.

1. Start with a brilliant shape. Round, oval, cushion, princess or radiant; skip SI2 for emerald and Asscher cuts.
2. Read the plot. Look for small, light-coloured inclusions near the edge, not dark ones under the table.
3. Check the comments. A note about clouds not shown means you need to confirm the stone is not hazy.
4. Look for durability risks. Avoid feathers that reach the girdle, corners or a point.
5. Watch a video, then view it face-up. Judge it at 25–30 cm, the way you will see it on the hand.
6. Confirm there is no undisclosed treatment. The report should note any laser drilling; walk away from fracture-filled stones unless it is disclosed and priced accordingly.