SI1 Diamond Clarity: Does It Still Look Good?

Last Updated on May 22, 2023 by Juli "Jewels" Church

Wanting to know if SI1 clarity is a good clarity grade for a diamond engagement ring?

You're in the right place. I'll tell you everything you need to know about purchasing SI1 diamonds and answer questions like: 

si1 diamond clarity
  • What are SI1 diamonds?
  • Are SI1 diamonds better than VS1 diamonds
  • Are SI1 diamonds eye clean?

What is an SI1 Diamond?

An SI1 diamond is a diamond whose clarity grade has been determined as Slightly Included. Slightly Included Diamond Clarity is made of two grades, SI1 diamonds and SI2 diamonds.

A Word on Diamond Clarity

A diamond's clarity grade is determined by the natural inclusions present in the diamond. This includes both internal inclusions and surface blemishes.

GIA Diamond Clarity Scale

An SI1 diamond is one clarity grade above SI2 diamonds on the Gemological Institute of America's Diamond Clarity scale. The SI diamond clarity tier is sandwiched between Included diamonds and Very Slightly Included diamonds.

SI1 Clarity vs SI2 Clarity Grades

You already know SI diamond clarity is made of SI1 and SI2 diamonds. Though the average person may not be able to tell the difference when lying side by side, there are some differences between the two grades to consider before making your final choice.

SI1 diamond clarity is likely to have less prominent inclusions than in SI2 diamond clarity. Both diamonds are able to have small inclusions that may be seen with the naked eye.

But visible inclusions in a SI1 diamonds tend to be toward the outer edge of the diamond or easily noticeable inclusions that are harder to see because of where they are.

SI2 diamonds are going to be more likely to have inclusions toward the center. These may or may not be apparent from normal viewing distance, depending on your own detection. Typically, if you're looking for inclusions, you'll be able to find them much easier.

Many people don't notice noticeable inclusions until much later. Too often have I seen customers yell at us at Kay Jewelers because they swore up and down that "black spot" in their diamond engagement ring wasn't there when they bought it.

The problem is all the lighting in those jewelry stores are meant to bring out the sparkle and best light performance of all the diamonds. But when you get into normal viewing light and other different kinds of lighting, dark crystals can be more apparent to you.

Thought SI2 diamonds are more likely to have darker and more obvious inclusions, both diamond clarity grades are capable of being eye clean diamonds.

On average a SI1 diamond is usually at a 5-15% increase in price from an SI2 diamond. However, the price difference shifts if the other diamond grades are different.

Example of SI1 Clarity Diamond vs SI2 Clarity Diamond

1 Carat SI1 Clarity G Color, Radiant Cut, GIA Report

1.02 Carat SI2, G Color, Radiant, GIA Report

SI3 Diamond Clarity Grades

Every so often I hear people talk about the so-called SI3 clarity grades. The GIA doesn't standardize this diamond grade in their gemological reports and most labs don't. But as more diamond buyers take to online diamond retailers to find the perfect diamond for their engagement rings, you may come across a lab that awards SI3 Clarity grades.

It's my recommendation and personal opinion that you should avoid these diamonds like The Plague.

  1. If the GIA, IGI, and AGS gemological labs don't have SI3 clarity grades, then you shouldn't purchase a diamond with one. These are reliable and respected grading reports.
  2. The reason why SI3 diamonds exist is to simply extend the clarity grade. But in actuality, diamonds with SI3 clarity are equivalent to what the GIA would describe as I1 diamonds.
  3. Retailers and labs that offer so-called SI3 clarity diamonds are really just dressing up lower clarity grade diamonds to pass them off as higher quality. I'd consider that more of a deceptive practice.

According to the GIA, they routinely analyze what some would call SI3 diamonds to see if a change in the scale is needed — and they've determined it unnecessary.

SI1 Clarity Grade vs I1 Clarity Grades

When you shop at a brick and mortar store like Kays and Zales, you're more likely to run into engagement rings with SI clarity grades or I clarity grades. I clarity grades are included, and have eye visible inclusions seen with the naked eye.

The I clarity tier is made of three clarity grades: I1, I2, and I3 clarity. I1 and I2 diamonds are typically reserved for small accent diamonds and melee stones in engagement rings at commercial mall retailers.

Majority of the engagement rings in these mall retailers store are actually I1 clarity grades, the lowest on the GIA's diamond clarity scale.

SI1 diamonds are higher clarity grades than I1 clarity grades. While both diamond grades are capable of having inclusions play a major part in their diamond's appearance, you'll have a much harder time trying to find an eye clean diamond with an I1 clarity grade.

I1 clarity diamonds typically have many noticeable inclusions. Many online diamond retailers won't offer I1 clarity diamonds because they don't considered them good quality. I1 clarity diamonds range from 10-30% cheaper than an SI1 diamond of similar quality and grades.

Examples of SI1 clarity Diamond vs I1 Clarity Diamond

1 Carat SI1 Clarity, GIA Graded, Round Cut, Excellent Cut at 40x magnification

1 Carat SI1 Clarity, GIA Graded, Round Cut, Excellent Cut at 40x magnification

SI1 Clarity Diamonds vs VS1 Diamonds

A VS1 diamond is the higher clarity grade of the Very Slightly Included clarity tier. VS1 diamonds are the higher of the two VS diamond clarity grades.

The clarity features of a VS1 diamond should not be seen with the naked eye. VS1 diamonds should always be eye clean. SI1 diamonds may or may not be eye clean.

Very Slightly included diamonds still have inclusions, but they are very small inclusions able to be seen at 10x magnification and beyond.

Typically, I recommend buying a diamond with VS1 or VS2 clarity grades because they should always be eye clean. But if you have the patience and need the savings, digging for an eye clean SI1 clarity diamond is still doable.

After all, the average price difference between a VS1 and SI1 diamond is around a 20-30% increase.

Examples of SI1 Clarity Diamond vs VS1 Clarity Diamond

Oval, G Color, VS1 Clarity, GIA Graded, 1.01 Carats, small light pinpoints

Oval, F Color, VS1 Clarity, GIA Graded, 1.01 Carats, small light pinpoints

SI1 Clarity Diamonds vs VVS1 Diamond Clarity

Slightly included diamonds are 4 clarity grades below Very Very Slightly included diamonds. VVS1 diamonds are the last clarity grade before internally flawless diamonds.

VVS1 diamonds are much rarer and higher value than a SI1 clarity diamond. They don't have any dark crystal inclusions under magnification either. The inclusions in VVS1 diamonds tend to be very light colored and often small pinpoints and feathers.

Even if an SI1 diamond is eye clean, it will most definitely have inclusions noticeable under 10x inclusions and beyond.

But just because a VVS1 diamond has less inclusions under magnification, doesn't necessarily mean its the better buy for you. You may not want to pay the premium that comes with purchasing a VVS1 clarity grade over an SI1 clarity diamond.

Examples of SI1 clarity Diamond vs VVS1 Clarity Diamond

SI1 Clarity, 1.05 ct, H Color, Princess Cut, GIA graded

VVS1 Clarity, 1.05 ct, H Color, Princess Cut, GIA graded, No Obvious Inclusions

Cost of an SI1 Clarity Diamond

Diamonds with an SI clarity grade are generally considered to be less expensive of the majority of diamond clarity grades.

I'd love to tell you that an SI1 clarity diamond costs XX amount and an SI2 diamonds costs XX amount. But the diamond world just doesn't work that way.

Diamond quality and diamond prices are determined by assessing many contributing factors. You may know the 4Cs of diamond quality, but each "C" has its own charts and rankings from most to least expensive.

But if you have high grades in color and carat weight, the cost of an SI1 diamond is likely to be a lot more than a 1 carat SI clarity grade diamond. The price of a diamond skyrockets the most when the carat weight is increased.

The 4Cs will affect the price of your diamond the most, but there's many other factors that may add or subtract a few hundred from your total. Some of these factors include:

  • Diamond Shape
  • Certified Diamonds vs Uncertified Diamonds
  • Certifying Grading Lab 
  • Brands
  • Retailer
  • Lab Grown Diamonds vs Mined Diamonds
  • Specialty Cuts
  • Colorless vs Fancy Color Diamonds
  • Proportions
  • Fluorescence
  • Treatment

But if you must have a number, a 1 carat SI1 clarity diamond may run you from $3,000 to $10,000 depending on individual grades and quality.

SI1 Clarity Lab Grown Diamond Prices

However, you can expect that price range to drop quite a bit if you set your sights on a lab grown diamond. Lab grown diamonds are real diamonds that are created in a lab by scientists emulating the earthly conditions it takes to grow natural diamonds.

Other than origin, lab grown diamonds have the same grades and features as mined diamonds. You're also more likely to come across eye clean SI1 diamonds that are lab grown because the inclusions are limited due to their isolated environment.

If ethical engagement rings are a concern, lab grown diamonds are 100% conflict free. They're not all completely sustainable, but use a lot less energy and fossil fuels than the diamond mining process.

But for many, the best part is that lab created diamonds can come at a 20-40% discount from mined diamonds of the same quality.

Where to Buy SI1 Clarity Diamonds

I recommend buying SI1 clarity diamonds online because it's a lot easier to find eye clean SI diamonds than in stores.

That being said, there's a new online diamond retailer popping up every day. Throw in private jewelers and marketplace sellers, it gets confusing on what sets each one apart. Never mind that legitimacy of them. So if you want some advice, check out our guide on where to buy SI clarity diamonds online.

SI1 Clarity FAQs

Are SI1 Diamonds Eye-Clean?

In general, SI1 diamonds aren't considered to be eye clean diamonds. The VS2 clarity grade is typically the first clarity grade that must be eye clean. However, SI1 clarity diamonds may have one or two more obvious inclusions that may be located near the outer edge.

Certain diamond shapes like brilliant cut diamonds can do better at hiding eye visible clarity features than with step cut diamond shapes like emerald cuts or Asschers. These shapes tend to have a large table facet, making it a lot easier to see clarity imperfections that impact the diamond's beauty. Round brilliant diamonds are excellent at hiding inclusions because of their superior light performance.

But as I've said before, just because the majority of SI1 diamonds aren't eye clean, doesn't mean there aren't eye clean SI1 diamonds to be found. And I'll tell you how to do just that.

Listen up.

How do you find an eye-clean diamond? 

Online diamond shopping is the way to go, if you haven't figured out the recurring theme by now. Plus, loose diamonds and empty ring settings allow you to be in control of your engagement ring instead of picking from preset engagement rings in the cases.

But the biggest reason why you should consult an online diamond retailer for eye clean SI1 clarity diamonds is because of how many they have in their inventory. There aren't many physical jewelry stores that are going to have hundreds of SI1 clarity diamonds and all the time in the world for you to look at each one.

No one.

But with online inventories, you can take all the time you need to narrow down your favorite SI1 diamonds. Plus, looking at high quality images and interactive 360˚ videos is so much easier than looking through a gem microscope or jeweler's loupe.

You'll have to keep in mind that the viewers online are typically beyond 10x. One of our favorites James Allen displays their loose diamonds at 40x magnification. Even VS1 diamonds may have larger inclusions at that magnification.

Fortunately, many of the viewers allow you to zoom out. This can help you when identifying clarity features in a diamond and then seeing if you can notice them from further away.

And if the viewer you have has an interactive feature, it will allow you to control the diamond angles to determine how the light and cut quality affect the appearance of inclusions.

By taking your time and observing each SI1 diamond closely, you can find an eye clean one in there, or at least one whose inclusions are barely noticeable. An engagement ring setting can also hide inclusions on the edges by positioning the prongs where it is.

And if you're really feeling ambitious, you can try to find an eye clean SI2 diamond, which is much harder.

My final piece of advice when finding eye clean diamond clarity for SI1 diamonds is to make sure to choose a retailer that has a good and EASY return policy, just in case your chosen SI1 diamond isn't what you thought. Always read the entire return policy process before purchasing.

Is SI1 clarity good for a 1-carat diamond?

The average carat weight for a center diamond lies somewhere between 1-2 carats. However, many choose a 1 carat diamond ring as their choice center carat weight.

SI1 clarity is typically a good clarity grade for a 1 carat diamond that is brilliant cut. The answer to this question becomes debatable as the diamond shape and grades change.

For example, even if you choose a round diamond with good cut quality, the diamond's clarity may not be as good than if you chose an Excellent cut round diamond.

If you haven't figured it out by now, there's not many direct answers when it comes to diamonds and gemstones.

There's many factors that attribute to a "good diamond" of quality, not just whether it's an SI clarity diamond or not.

The 4Cs of diamond quality is an excellent place to start in order to pick out some gorgeous SI diamonds. You already know about clarity, but color grade, carat weight, and cut quality are also highly relevant to your diamond's beauty.

What grading report should I get for an SI1 clarity diamond?

Not every engagement ring comes with a grading report, also known as diamond certification. In fact, majority of Kays and Zales have uncertified diamonds.

I don't recommend buying uncertified diamonds or diamonds certified by certain gem labs. But I definitely recommend buying a certified SI1 clarity diamond from a reputable gemological laboratory.

Diamond certification is important because it certifies the diamond you're paying for is the grades it's being advertised as. Without a grading report from a reliable laboratory, a retailer could be selling you any old diamond.

So, which labs should you avoid?

Let's just talk about which grading reports are recommended when purchasing SI diamonds. We recommend the following grading reports:

  • GIA (natural diamonds and lab diamonds)
  • IGI (lab grown diamonds)
  • AGS (natural diamond, rarely grades lab diamonds)
  • GCAL (lab grown diamonds)

All diamond certifications will either come with a physical or digital grading report. Some grading report numbers will be laser inscribed with a serial number for identification if stolen too.

You should know that a diamond grading report is not an appraisal. It's not jewelry insurance either. Light performance reports aren't diamond certificates either. These are extra documents that some retailers choose to include with your diamond documentation.

An SI1 clarity diamond grading report from the GIA may have the following information:

  • Shape and Cutting Style: The shape and cutting style of the diamond, such as round brilliant, princess, cushion, etc.
  • Measurements: The physical dimensions of the diamond, including its diameter, depth, and weight (in carats).
  • Carat Weight: The weight of the diamond, measured in carats.
  • Color Grade: The GIA color grade, which ranges from D (colorless) to Z (light yellow or brown).
  • Clarity Grade: The GIA clarity grade, which ranges from Flawless (FL) to Included (I3).
  • Clarity Plot: Clarity plots are diagrams showing the location and type of inclusions in the diamond.
  • Cut Grade: The GIA cut grade, which assesses the overall quality of the diamond's cut, including its proportions, symmetry, and polish.
  • Polish: The quality of the diamond's surface polish, graded as Excellent, Very Good, Good, Fair, or Poor.
  • Symmetry: The quality of the diamond's symmetry, graded as Excellent, Very Good, Good, Fair, or Poor.
  • Fluorescence: The strength and color of any fluorescence observed in the diamond under UV light.
  • Comments: Any additional comments or observations by the grader regarding the diamond's characteristics or features.
  • GIA Report Number: A unique report number assigned by GIA to identify the specific diamond and its associated grading report.
  • Security Features: The GIA grading report may also include security features, such as a hologram, to ensure its authenticity.
gia cert report

Note that not all GIA reports will include a cut grade. In some cases, the diamond may have been submitted for grading before the GIA introduced its cut grading system, or the diamond may not meet the criteria for a cut grade.

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