Gem Fountains Clarity Description

Gem-Fountain

Clarity descriptions at Gem-Fountain

Unlike diamonds, coloured gemstones naturally show very different internal features depending on the gem species. Some stones are typically crystal-clear, while others may show silk, veils, or a slight natural haze — even when no distinct inclusions are visible.

For this reason, clarity in coloured gemstones cannot be described with a single diamond-style scale. To keep our descriptions consistent and easy to understand, we use the TopGems ClarityType system developed by our Austrian partner company TopGems.

Transparency
Light passage
How well light passes through the stone
Gem type (I–V)
Inclusion likelihood
Natural inclusion tendency per species
Clarity grade
Visibility
How visible inclusions are to the eye
Example A product listed as Transparent / Type II / VSI combines all three building blocks.

Transparency of gemstones

Transparency describes how well light can pass through a gemstone. It depends on chemical composition, internal structure, and the presence of inclusions.

Term Light transmission Objects behind Optical effect
TransparentPasses completely without scatteringClearly and sharply visibleBrilliant clarity, sparkling reflections
Semi-transparentPasses evenly but is scatteredNo clear outlines; diffuse lightSoft glow, luminous colours
TranslucentPasses partially by thicknessFaintly visible in thin areasMilky appearance, diffused light
Semi-translucentSmall amount passes in thin areasObjects not visible; light spotsSubdued luminosity, waxy/foggy
OpaqueLight does not pass throughCompletely blockedDeep, saturated colour

Type classification

Based on the natural likelihood of inclusions for specific mineral species, to set realistic expectations.

Type Characteristics Examples Assessment
Type IRarely with visible inclusionsAquamarine, Citrine, TanzaniteInclusions highly detrimental to value
Type IIUsually small, visible inclusionsRuby, Sapphire, SpinelSmall inclusions are acceptable
Type IIITypically visible inclusionsEmerald, Rubellite, Red BerylNaturally tolerated characteristics
Type IVInclusion & effect stonesStar Ruby, Rutilated QuartzInclusions are desirable features
Type VMostly opaqueTurquoise, Jade, OnyxInclusions irrelevant for valuation

Type IV intensity scale — the optical effect (star, cat's eye, etc.) is rated from 1 to 5:

IV-1
Light
IV-2
Moderate
IV-3
Good
IV-4
Very good
IV-5
Excellent

Clarity grades

Describes the visibility of inclusions that may affect transparency and visual quality.

LC
Loupe clean
No inclusions at 10× magnification
EC
Eye clean
No inclusions to the naked eye
VVS
Very very small
Visible only under ideal lighting
VSI
Very small
Often invisible to the naked eye
SI
Small
Visible at certain angles; inconspicuous
MI
Moderate
Easily noticed; consistent pattern
OI
Obvious
Instantly visible internal features
DI
Distinct
Strongly affects stone appearance
ND
Not detectable
Low or no transparency; no grade possible

How the three building blocks combine

Semi-Transparent / Type II / EC Moonstone or a Kashmir sapphire that is eye clean aside from a slightly milky appearance.
Transparent / Type IV-4 / OI A rutilated quartz with a well-defined star rutile inclusion, along with other obvious visible internal features.
Semi-Translucent / Type V / ND Describes a top-quality turquoise with semi-translucent body.
Transparent / Type III / MI Emerald with the typical jardin (garden-like inclusion pattern).
This grading approach offers an innovative way to describe gemstones in greater detail based on their internal characteristics.

Last Updated: 01.2026

Questions?

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    CONTACT INFORMATION

    Gem Fountain – Market Desk (Chan Gems Building)
    A112, Chan Gems Building, Wat Mai,
    Mueang Chanthaburi District,
    Chanthaburi 22000, Thailand

    Whatsapp/Phone: +66 95 235 9871

     

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