Last Updated on September 2, 2022
When shopping for a diamond, there are four primary factors to consider before making your decision: color, cut, carat, and clarity.
Clarity refers to the light performance of a diamond and can impact the overall appearance of a diamond.
That’s why selecting the proper clarity grade is essential when it comes to choosing a diamond.
SI1 and VS1 diamonds are two common clarity grades on the Gemological Institute of America (GIA) grading scale.
Both grades of diamonds have important distinctions to consider.
Here’s a look at the differences between SI1 and VS1 diamonds and what you need to know before making your purchase.
What Are SI1 Diamonds?
SI1 (slightly included) diamonds have visible blemishes, known as inclusions. The inclusions can be seen under 10x magnification.
SI1 diamonds sit between VS2 (very slightly included) and SI2 (slightly included) diamonds on the GIA clarity grading chart.
Diamonds with an SI1 clarity grading will likely have multiple inclusions, which may vary in size, shape, and location.
Inclusions on an SI1 diamond may include:
- Black spots
- Crystals
- Feathers
- Cavities
- Needles
- Twinning wisps
SI1 diamonds may have multiple inclusions of the same type in one area or a mixture of many different inclusions spread throughout the diamond.
A professional gemologist will evaluate the severity of the inclusions using a variety of factors to determine the clarity grade of the diamond.
These factors include:
- Size
- Shape
- Position
- Visibility
Additional consideration will be given to how impactful an inclusion is to the light performance and durability of the diamond.
The details of the inclusions found on an SI1 diamond are documented in the GIA grading report.
What Are VS1 Diamonds?
VS1 diamonds (very slightly included) have inclusions that are hardly visible when under 10x magnification.
VS1 diamonds sit between VVS2 (very, very slightly included) and SI1 (slightly included) diamonds on the GIA clarity grading chart.
VS1 diamonds have inclusions that typically remain invisible to the naked eye and require a gemologist to scan the diamond multiple times to locate the inclusions.
Diamonds with a VS1 clarity grading may have a cluster of the same type of inclusion or may have different inclusions throughout the diamond.
VS1 diamonds can have inclusions of all types, such as:
- Feathers
- Cavities
- Etch channels
The inclusions on VS1 diamonds have less impact on the light performance and durability of the diamond and will be notated on the GIA grading report.
Differences Between SI1 and VS1 Diamonds
Both SI1 and VS1 diamonds are common clarity grades. However, there are a few fundamental differences between the two, including:
Amount of Inclusions
The biggest difference between an SI1 and VS1 diamond is the number of inclusions.
VS1 diamonds will typically have fewer inclusions than SI1 diamonds. However, it is possible for an SI1 diamond to have one or two prominent inclusions.
Inclusions may be present on the crown, pavilion, or table of the diamond.
Most VS1 diamonds will have small inclusions that can be easily covered by a ring setting, while SI1 diamonds will have a higher number of inclusions that are visible to the naked eye.
Performance
Another big difference between SI1 and VS1 diamonds is the impact of the inclusions on the performance of the diamond.
VS1 diamonds appear eye-clean, meaning more often than not inclusions are hidden from the naked eye, especially if under two carats.
However, inclusions may be visible on larger VS1 diamonds over two carats.
Additionally, inclusions found on a VS1 diamond are less likely to impact the overall performance of the diamond and will have minimal impact on brilliance and durability.
Conversely, because SI1 diamonds have a larger number of inclusions, they are much more likely to impact the overall performance of the diamond.
Inclusions on SI1 diamonds may be visible to the naked eye, especially on diamonds with larger carat weights.
Additionally, an inclusion located on a delicate area of the diamond, such as a thin girdle, can impact the durability of the diamond and make it more susceptible to chipping and breaking.
Price
The last difference between SI1 and VS1 diamonds is the price.
Because VS1 diamonds have fewer inclusions than SI1 diamonds, they are 18% more expensive on average than SI1 diamonds.
However, the grade of a diamond should not be the primary factor when deciding which clarity grade to purchase.
Some VS1 and SI1 diamonds will look identical.
As a rule, it’s better to select a diamond that appears eye-clean rather than selecting a diamond based solely on clarity grading.
