The diamond clarity scale developed by GIA is divided into the
following categories:

Flawless or FL: This category encompasses diamonds without blemishes or inclusions, representing the highest clarity grade.
Internally Flawless or IF: Within this grade, diamonds exhibit minimal external blemishes and no internal inclusions. It stands at the pinnacle of clarity.
Very Very Slightly Included 1 or VVS1: Diamonds with this grade possess an incredibly high clarity level. Inclusions are nearly impossible to spot without a microscope of 60-100X magnification, often requiring trained gemologists. As natural birthmarks, inclusions are as unique as fingerprints, contributing to the diamond's individuality.
Very Very Slightly Included 2 or VVS2: Similar to VVS1, this grade indicates high clarity. Inclusions are hard to identify without a jeweler's loupe; even gemologists might require a high-magnification microscope. A VVS2 diamond's inclusions are usually not easily discernible with a loupe.
Very Slightly Included 1 or VS1: Among the top clarity grades, VS1 diamonds are entirely eye-clean and esteemed as investment-grade, comparable to VVS stones. The line between VVS2 and VS1 is subtle, making them closely matched in quality.
Very Slightly Included 2 or VS2: Optimal for quality on a budget, VS2 offers excellent clarity. Diamonds in this range are eye-clean, particularly in sizes under 2 carats, making them an attractive choice for larger diamonds without compromising quality.
Slightly Included 1 or SI1: For 1-carat diamonds, SI1 can maintain eye-clean status when graded by GIA. In the 2-carat range, scrutinizing the clarity grade's impact on brilliance is essential. SI1 provides budget-friendly options with eye-clean appearances.
Slightly Included 2 or SI2: Eye-clean SI2 diamonds exist in the 1-carat range, depending on inclusion type and location. In the 2-carat range, finding truly eye-clean SI2 diamonds can be challenging. Close inspection is vital before purchase.
Included 1-3 (I1, I2, I3): This range represents the lowest clarity grades. Diamonds here are not eye-clean, often resulting in compromised brilliance and fire due to multiple flaws. While I1 could be acceptable for budget constraints, I2/I3 diamonds might not be advisable.