Understanding Sapphire Clarity, Size, and Treatments: A Complete Guide for Gem Buyers

What Does “Eye Clean” Mean for Sapphires?

When a sapphire is described as “eye clean,” it means no visible inclusions or imperfections are noticeable to the naked eye. While tiny internal features may exist, they can only be seen under magnification.
An eye-clean sapphire appears flawless in everyday wear, letting its natural brilliance and color truly shine.

How to Visualize Gemstone Sizes for Jewelry Design

Carat weight can be misleading—two sapphires may weigh the same but appear very different in size due to their cut and depth. Instead, focus on millimetre measurements (length × width × depth) for a more accurate visual comparison.

Helpful Tools:

• Printable Gem Size Charts – Show true-to-life outlines of shapes.

• Online Visualization Tools – Interactive previews via GIA or Stuller.

• Custom Ring Comparison – Helps plan proportions for your setting and finger size.

💎 At NashGems, our gem experts can help you find the ideal size and shape for your dream design.

How Are Gemstones Inspected for Clarity Compared to Diamonds?

Sapphire clarity is judged without magnification—a gemstone is held about 12 inches from the eye and examined under light. Only inclusions visible from the crown (top) are considered.
This provides a realistic assessment of how the gem will look once set, emphasizing natural beauty over lab perfection.

Understanding Sapphire Dimensions: Length, Width, and Depth

• Length: Longest side of the gemstone

• Width: Shorter side measurement

• Depth: Height from top (table) to bottom (culet)

Round and square sapphires have equal length and width, giving a balanced face-up appearance. These proportions affect brilliance, symmetry, and how the sapphire will look when set.

Heated vs. Untreated Sapphires: What’s the Difference?

Most sapphires (over 99%) are heat treated to improve color and clarity—a permanent and accepted enhancement.
Untreated sapphires, by contrast, are incredibly rare and command higher prices due to their natural state.

At NashGems, every sapphire includes clear treatment information in its specifications, so you know exactly what you’re purchasing.

Why Use Millimetres Instead of Carat Weight?

Carat measures weight, not size. Because sapphires vary in depth and cut, two stones of the same carat weight can look very different.
Millimetre dimensions give a true sense of size, especially important for online shoppers comparing different shapes like oval, cushion, or emerald cuts.

Carat Weight vs. Dimensions: Which Matters More?

• Carat Weight = gemstone mass (5 carats = 1 gram)

• Dimensions (mm) = visible size (e.g., 7×5×3 mm)

A deep sapphire may weigh the same as a shallow one but look smaller when viewed from above. Always check millimetre size for an accurate sense of appearance—especially if you’re selecting a stone for a ring.

Eye Clarity Grades for Gemstones