Extra Facet
Extra Facet
A deliberate addition to the polishing plan, balancing clarity against symmetry
An extra facet is a small, unplanned polishing surface added to a finished gemstone outside the geometry prescribed by its cutting style. It appears most commonly on the pavilion or girdle, and its purpose is almost always practical: to grind away or reduce the visibility of a surface-reaching inclusion, chip, or abrasion that would otherwise compromise the stone's clarity or durability. The decision to cut an extra facet reflects a deliberate trade-off — the cutter accepts a minor departure from symmetrical facet arrangement in exchange for a cleaner face-up appearance or a heavier finished weight.
Where Extra Facets Occur
Extra facets are found on all gem materials, from diamonds to coloured stones, and their placement follows the logic of the blemish they are meant to address. On the pavilion, they are typically small and oblique, tucked between main facets so as to be invisible when the stone is viewed table-up. On the girdle, they may appear as a flattened or angled departure from the otherwise continuous girdle plane, often placed precisely where a feather or surface chip was present in the rough. Less commonly, extra facets appear on the crown, where they are more visible and therefore a less favoured solution.
Extra Facets in Diamonds
In diamond grading, extra facets are classified as a surface feature — a blemish category — rather than an internal inclusion. The GIA clarity grading system notes extra facets on grading reports and may plot their location on the diagram. Their impact on the clarity grade itself is generally minor, since they do not represent internal disruption to the crystal; however, they are relevant to the symmetry grade, where their presence can lower an otherwise high assessment. A stone with Excellent polish and a well-placed extra facet on the pavilion may still achieve a symmetry grade of Very Good rather than Excellent, depending on the facet's size and conspicuousness. Buyers of high-make diamonds — particularly those seeking triple-Excellent or "hearts and arrows" precision — therefore pay close attention to extra facet notations on laboratory reports.
Extra Facets in Coloured Gemstones
The coloured-stone trade takes a considerably more relaxed view. Because coloured gemstone cutting has historically prioritised colour saturation and weight retention over strict geometric symmetry, extra facets are commonplace and widely accepted. A ruby with a small extra facet on its pavilion, placed to eliminate a surface-reaching fracture, is regarded as a well-considered piece of craftsmanship rather than a flaw. Coloured-stone laboratory reports from organisations such as Gübelin, SSEF, and Gemmological Institute of America may note extra facets descriptively, but they rarely influence the overall quality assessment in the way they might for a diamond symmetry grade.
In calibrated commercial goods — stones cut to standard millimetre dimensions for setting in mass-produced jewellery — extra facets are sometimes introduced simply to preserve weight when a piece of rough is slightly irregular. Here the extra facet serves yield rather than clarity, and its presence is unremarkable in the trade.
Relationship to Related Features
Extra facets are distinct from naturals, which are unpolished remnants of the original crystal surface left deliberately on the girdle to preserve weight. Both are concessions to the geometry of the rough, but a natural is an absence of polishing whereas an extra facet is an addition to it. Extra facets are also distinct from polishing remnants — faint, unintended polish marks left by an improperly oriented lap — which are surface blemishes rather than intentional cuts. Understanding these distinctions matters when reading a laboratory grading report, since each feature carries different implications for the cutter's intent and the stone's overall make.
Practical Considerations for Buyers
- An extra facet on the pavilion of a coloured stone is rarely visible face-up and is generally of little concern.
- An extra facet on the crown or table is more visible and warrants closer inspection.
- In diamonds, the location and size of an extra facet should be assessed in the context of the full symmetry grade, not treated as an automatic disqualifier.
- Extra facets can occasionally create unwanted light leakage if they disrupt the critical-angle geometry of the pavilion, particularly in step-cut stones where the pavilion facets are large and precisely angled.
- When a stone is being reset or repolished, a skilled lapidary may be able to incorporate an extra facet into a revised facet arrangement, effectively eliminating it — though this will reduce the stone's weight.