Naturals (plural) are the unpolished remnants of original crystal surface intentionally retained on a faceted gemstone, most commonly on a diamond's girdle. Where the singular term natural describes a single retained patch, the plural usage covers stones on which two, three, or more naturals are visible, and the cutter's decision-making process when working with rough that requires multiple retained patches to optimise the finished stone. Naturals are routinely encountered on diamonds — particularly larger stones, fancy shapes, and stones cut for weight retention — and somewhat less frequently on faceted coloured stones cut from rough that retains identifiable crystal surfaces.

Why cutters retain multiple naturals

The decision to retain multiple naturals on a single stone follows from the rough's geometry. A diamond crystal in octahedral, dodecahedral, or macle form has crystal surfaces oriented in specific directions; the cutter who is optimising for weight retention will preserve as much of the original surface as possible while still producing a stone of acceptable proportions and finish. On larger crystals — particularly those over five carats in cut weight — the cutter may retain three or four naturals at different positions around the girdle to push finished weight up while preserving diameter and avoiding inclusions. The economics often justify the trade-off: a 5.30-carat finished stone with four small naturals at the girdle may price higher than a 4.95-carat stone of the same clarity and colour with cleaner girdle, even after the modest grade impact of the naturals.

Distribution and grading

The position of naturals around the girdle affects both grade and visual character. Naturals distributed evenly around the girdle (at the four principal compass points, for example) are aesthetically less disruptive than concentrated naturals (all at one quadrant), even at the same total area. Indented naturals — those that extend below the girdle plane — affect grade more than flush naturals, because they disrupt the girdle outline and visibly reduce the stone's diameter at the indented points. GIA, AGS, and other major laboratories plot all naturals on the inclusion map regardless of indentation, but indented naturals receive specific notation and may affect the symmetry grade in addition to the clarity grade.

For symmetry grading, the question is whether the naturals together produce visible asymmetry in the girdle profile. A stone with four small naturals symmetrically placed may show no symmetry penalty; a stone with one large natural on one side and a clean girdle elsewhere may be downgraded for the visible asymmetry. The grading judgment is made on the stone as a whole rather than on individual feature-by-feature evaluation.

Identification under magnification

Multiple naturals on a single stone show three diagnostic features that distinguish them from polishing artefacts. First, the trigon etch pattern: the triangular etch markings characteristic of natural diamond crystal surfaces are visible on naturals at sufficient magnification (10x or higher) and are not produced by polishing or by other modifications. Second, the surface texture: naturals show a frosted, matt surface contrasting sharply with the high polish of the surrounding girdle, and the contrast remains under microscopic examination. Third, geometric consistency: naturals on a single stone often show parallel or geometrically related orientations that follow the original crystal's symmetry, since they are remnants of crystallographically related surfaces of the original rough.

Fancy-shape and large-stone considerations

Naturals are particularly common on certain fancy-shape diamonds. Marquise, pear, and oval cuts cut from elongated rough often retain naturals at the points or along the longer axis of the girdle, where the cutter is preserving the rough's original elongated geometry. Emerald and Asscher cuts retain naturals at the corner positions where the cutter has trimmed the rough to fit the rectangular outline. Rose cuts and step-cut shapes designed for very large rough — particularly historical cuts on Indian and Brazilian alluvial stones — may retain extensive areas of original surface, in some cases representing a substantial fraction of the total girdle area.

On large stones (above five carats), the economics of natural retention are particularly favourable. The price per carat at higher weights increases sharply at recognised price points (5, 10, 15 carats), and small weight increments can produce substantial value increases that justify retaining naturals that affect grade modestly.

Coloured-stone naturals

Faceted coloured stones cut from rough that retains identifiable crystal surfaces — sapphire, ruby, emerald, tourmaline — also exhibit naturals, though the term is used less commonly in coloured-stone trade than in diamond trade. The principle is the same: the cutter retains crystal surface to preserve weight or to avoid inclusions, with the resulting unpolished area appearing as a frosted patch on the girdle. Coloured-stone naturals are less subject to formal grading conventions than diamond naturals, since coloured stones are not graded on cut and clarity to the same standardised framework as diamonds.

Trade convention

The trade convention is that naturals are minor blemishes acceptable in commercial stones, particularly at higher weights, and that they should be disclosed in grading reports and trade communication where they affect grade. Larger naturals or numerous indented naturals should be flagged in description; small flush naturals are routinely accepted without specific disclosure. Buyers and dealers reading grading reports use the inclusion plot to assess the position and prominence of naturals, and judge each stone on its overall finish profile.

Further reading

• GIA — Diamond clarity grading reference
• GIA Gems & Gemology — diamond cutting and surface-feature articles
• International Gem Society — diamond grading reference