Gemstone Clarity & Colour Explained
ZGems education · Updated
Clarity describes internal and surface features; colour describes a stone’s hue and appearance. Diamond grading labels and coloured-gem descriptions serve different purposes. Read them within the right material and grading system, then compare the actual stone.
What clarity can tell you
Internal features are called inclusions, and surface features are often called blemishes. Their visibility and location matter when you assess a stone’s appearance. A written grade is useful evidence, but it does not replace seeing the selected stone or understanding its condition.
For a coloured gem, ask about transparency, visible inclusions and any features that may affect wear or setting. A clearer appearance is not proof that a gemstone is natural, lab-grown or untreated.
What does eye-clean mean?
Eye-clean is an appearance description: inclusions are not visible to the unaided eye under the seller’s stated viewing conditions. Ask about the viewing distance, lighting and direction. A stone can look clean from above while showing features from the side or under magnification.
Eye-clean does not mean flawless, and it is not a diamond clarity grade. When comparing two stones, request similar lighting and viewing conditions so the description is meaningful to you.
Diamond clarity grades: read the exact report
| Label | Meaning |
|---|---|
| FL | Flawless: no inclusions or blemishes visible to a skilled grader at 10×. |
| IF | Internally Flawless: no inclusions visible at 10×; surface blemishes may remain. |
| VVS1 / VVS2 | Very, Very Slightly Included. |
| VS1 / VS2 | Very Slightly Included. |
| SI1 / SI2 | Slightly Included. |
| I1 / I2 / I3 | Included. |
Diamond clarity assessment considers features under controlled conditions, including magnification. See GIA: Diamond Quality Factors. Reporting formats vary by laboratory; use the terminology on the actual report.
Do not automatically transfer these diamond grades to every sapphire, ruby or emerald. If a coloured-stone seller uses VVS or VS, ask what system and inspection method they mean.
The D–Z diamond colour scale
| Grades | Colour grouping |
|---|---|
| D–F | Colourless |
| G–J | Near colourless |
| K–M | Faint |
| N–R | Very light |
| S–Z | Light |
These groupings describe the normal D–Z diamond colour range; fancy-colour diamonds are assessed differently. See GIA 4Cs: Understanding Diamond Color. The letters are not colour grades for sapphires, rubies or emeralds.
Compare coloured gems on their own terms
For a coloured stone, note the hue, lightness or darkness, strength of colour, transparency and how evenly the colour appears. Then compare the cut, dimensions and visible features alongside those observations.
Use our gemstone colour guide to build a preference rather than chasing a universal “best” grade. Ask what independent evidence supports origin, treatment or a special colour designation when those details matter to your purchase.
Questions to ask about a ZGems listing
- Which material and creation method are stated for the selected stone?
- Is “Eye Clean”, “VVS1” or another term a catalogue description or an assessment on an individual report?
- Can I see the selected stone in a photo or video, and what are its millimetre dimensions?
- Are treatments disclosed, and is an independent report available?
- For jewellery, do the specifications refer to the centre stone or all stones in the piece?
For report interpretation, IGI: How to Read a Laboratory Grown Diamond Report shows the information an IGI diamond report can contain. A reference to IGI here does not mean every ZGems item has an IGI report.
Explore the next step
Compare gemstones · Lab-grown diamond guide · gemstone cuts guide · custom jewellery design · gemstone education hub