Clarity in colored gemstones works very differently from diamond clarity. While diamond clarity follows a strict GIA scale from FL (Flawless) to I3, colored gemstone clarity is evaluated relative to what is normal for that particular gem type. An emerald with small inclusions can be considered "excellent" clarity, while a topaz with the same inclusions would be graded poorly.
What Is "EC" (Eye Clean)?
EC stands for "Eye Clean" — one of the most common clarity designations you will encounter when shopping for colored gemstones.
An eye-clean gemstone has no inclusions visible to the unaided eye when viewed face-up at a normal viewing distance of about 10-12 inches. Inclusions may be present under 10× magnification, but they do not affect the stone's beauty or transparency when viewed normally.
For most colored gemstones — especially Type II and Type III gems like rubies, sapphires, and emeralds — "Eye Clean" represents very good to excellent clarity and commands strong prices. It is the standard most shoppers should aim for.
Gemstone Clarity Grade Scale
While there is no single universal scale, the following grades are widely used in the colored gemstone trade:
| Grade | Full Name | Description |
|---|
| IF | Internally Flawless | No inclusions visible under 10× magnification. Extraordinarily rare in colored gemstones. Expect a significant price premium. |
| VVS | Very Very Slightly Included | Minute inclusions that are extremely difficult to detect under 10× magnification. Considered "almost loupe clean." Premium quality. |
| VS | Very Slightly Included | Minor inclusions visible under 10× magnification but difficult to find. Eye-clean. Excellent quality and value. |
| SI | Slightly Included | Noticeable inclusions under magnification. Usually eye-clean for Type I gems, may show inclusions in Type III gems. |
| EC | Eye Clean | No inclusions visible to the unaided eye. A practical trade grade indicating the stone looks clean in normal viewing. Very desirable for all gem types. |
| SI1 / SI2 | Slightly Included 1-2 | Inclusions noticeable under magnification. SI1 is usually eye-clean; SI2 may show faint inclusions to the naked eye. |
| I1 | Included (minor) | Inclusions visible to the naked eye but do not severely affect beauty or transparency. |
| I2 | Included (moderate) | Obvious inclusions that may reduce brilliance. Commonly seen in commercial-grade goods. |
| I3 | Included (severe) | Prominent inclusions that significantly affect transparency, brilliance, and potentially durability. |
| TS | Translucent | Very heavy inclusions that block light transmission. The stone appears cloudy or milky. |
| O | Opaque | No light passes through the stone. Typical for ornamental gems (jade, turquoise) but undesirable for transparent gems. |
The Type I / II / III Classification
Not all gemstones form under the same geological conditions. Some grow virtually inclusion-free, while others almost always contain visible inclusions. GIA developed a three-type classification system to set appropriate clarity expectations for each gem species:
| Type | Clarity Expectation | Gemstone Examples |
|---|
Type I
Usually Clean |
Typically eye-clean with no visible inclusions. Expect high clarity; inclusions are a significant negative. |
Aquamarine, Morganite, Heliodor (Yellow Beryl), Tanzanite, Blue Zircon, Smoky Quartz, Green Tourmaline, Imperial Topaz, Citrine |
Type II
Usually Included |
Commonly contain inclusions. Eye-clean specimens are very desirable and command a premium. Minor inclusions are normal and accepted. |
Ruby, Sapphire, Alexandrite, Garnet (most varieties), Iolite, Peridot, Rhodolite, Spinel, Tourmaline (most colors), Amethyst |
Type III
Almost Always Included |
Inclusions are expected and accepted. Eye-clean specimens are exceptionally rare and valuable. Moderate inclusions do not significantly lower value. |
Emerald, Red Beryl (Bixbite), Rubellite Tourmaline, Watermelon Tourmaline, Sphene |
What This Means for You
Practical clarity buying guide:
- Type I gems (aquamarine, tanzanite, citrine): Insist on eye-clean (EC) or better. Visible inclusions are unusual and indicate lower quality.
- Type II gems (ruby, sapphire, spinel): Eye-clean (EC) is excellent and a great target. Minor inclusions visible under magnification are perfectly normal and don't diminish the stone.
- Type III gems (emerald, rubellite): Some inclusions visible to the eye are normal and expected. The French term "jardin" (garden) is used to describe emerald inclusions — they are part of the stone's character. Focus on whether inclusions detract from the overall beauty.
Important Note About Lab Reports
Most colored gemstone reports from major labs like GIA and GRS do not include a formal clarity grade. They describe the stone's transparency and may note specific inclusions, but they do not assign a letter grade the way diamond reports do. The clarity grades listed above (EC, VVS, VS, etc.) are trade terms used by dealers, auction houses, and retailers to communicate clarity quality.
This is why understanding these terms matters — you cannot rely on the lab report alone to tell you how clean a gemstone is. You must either evaluate the stone yourself (in person or via high-quality imagery) or rely on a trusted jeweler's assessment.