The bullet cabochon — sometimes called a bullet cab — is a non-faceted gemstone cut characterised by a steeply rising, rounded dome that tapers to a distinct point at its apex, producing a profile closely resembling the ogive of a rifle bullet. It belongs to the broader family of cabochon cuts and is most accurately understood as a heightened variant of the sugarloaf, distinguished from that form by its more pronounced taper and sharper terminal point. Though less prevalent in commercial production than the standard oval or round cabochon, the bullet cabochon occupies a considered place in designer and bespoke jewellery, particularly where optical phenomena — asterism, chatoyancy, or adularescence — are the central concern of the piece.

Geometry and Proportions

In a conventional cabochon, the dome rises from a flat or slightly convex base to a rounded crown, with the height-to-width ratio typically ranging from low (almost flat) to medium. The sugarloaf pushes this ratio higher, producing a distinctly pyramidal silhouette. The bullet cabochon extends this logic further still: the sides converge at a steeper angle, and the apex is drawn to a more concentrated point rather than the gently rounded summit of the sugarloaf. Viewed in profile, the outline traces a smooth, continuous curve from the girdle to the tip, with no abrupt shoulder or flat table interrupting the ascent.

The base of a bullet cabochon is generally flat, allowing the stone to seat securely in a bezel or collet setting. The girdle outline — the footprint of the stone — may be round, oval, or occasionally pear-shaped, with round and oval being most common. Because the cut demands a significant depth of rough material relative to its face diameter, it is not economical for all gem species; it is most often employed when the rough is already of high-dome character, or when the cutter deliberately sacrifices yield to achieve the desired optical result.

Optical Rationale

The primary justification for the bullet cabochon's steep geometry is optical. In gems that display chatoyancy — the cat's-eye effect produced by parallel fibrous inclusions or hollow tubes — a high dome concentrates the reflected light band more sharply and positions it closer to the apex of the stone. Chrysoberyl cat's-eye, tourmaline cat's-eye, and cat's-eye apatite all benefit from this geometry: the taller the dome relative to the stone's width, the more precisely the silk is oriented and the more vivid the eye appears when the stone is viewed under a single light source.

Similarly, in asteriated stones — most notably star sapphire, star ruby, and star diopside — the intersection of two or more sets of needle-like inclusions produces a multi-rayed star. A high dome raises the apparent star toward the viewer and sharpens the rays, because the curved surface acts as a focusing lens over the oriented rutile or other silk. The bullet cabochon's pronounced apex can serve as a visual anchor for the star's centre, lending the phenomenon a sense of precision and depth that a flatter dome cannot achieve.

For adularescent materials such as moonstone (orthoclase feldspar), the interplay of light between alternating structural layers produces a billowing, floating glow. A high dome increases the path length of light through these layers and can intensify the three-dimensional quality of the adularescence, particularly the coveted blue sheen seen in fine Ceylonese moonstone. The bullet form, by concentrating this glow toward the apex, gives the stone a lantern-like quality that designers have found compelling in pendant and ring applications.

Materials Commonly Cut in This Form

• Chrysoberyl cat's-eye — the benchmark chatoyant gem; the bullet form is used for exceptional specimens where the cutter wishes to maximise eye sharpness and position.
• Star sapphire and star ruby — corundum with dense rutile silk; a high bullet dome can produce a star of exceptional clarity and centring.
• Moonstone — particularly high-clarity, strongly adularescent material from Sri Lanka or India; the form suits pendant drops and solitaire ring centres.
• Alexandrite and colour-change garnets — occasionally cut in bullet form when the material is translucent and the cutter wishes to emphasise depth of colour rather than brilliance.
• Tourmaline — cat's-eye tourmaline in particular, where the fibrous inclusions run parallel to the c-axis and a high dome sharpens the band.
• Opal — boulder and crystal opal are sometimes cut to a bullet profile to preserve play-of-colour depth, though the fragility of the apex requires careful setting.

Opaque materials — onyx, turquoise, malachite — are rarely cut in bullet form, as the optical rationale is absent and the pointed apex presents a practical vulnerability in wear.

Relationship to the Sugarloaf Cut

The distinction between a bullet cabochon and a sugarloaf is one of degree rather than kind, and the two terms are sometimes used interchangeably in the trade, which can cause confusion. The sugarloaf — named after the conical compressed-sugar loaves once common in European commerce — typically has a more pyramidal, four-sided or gently rounded form with a blunter apex. The bullet cabochon is rounder in cross-section and tapers more acutely, with a profile that is continuously curved rather than faceted or angular. In practice, a cutter producing a very high, round-based, sharply pointed stone will generally call it a bullet cab; a squarish or gently pointed high dome is more likely to be described as a sugarloaf. Neither term is formally standardised by any major gemmological body, and usage varies between cutters, dealers, and auction cataloguers.

Setting Considerations

The bullet cabochon's pointed apex presents specific challenges for the jeweller. A full bezel setting that encases the girdle is the most secure option and the most commonly used, protecting the stone's widest circumference while leaving the dome fully exposed. The apex itself must remain unencumbered by metal, both to preserve the optical effect and to avoid chipping — a pointed tip in any gemstone is a stress concentration point vulnerable to impact. For this reason, bullet cabochons are more frequently seen in pendants and earrings, where the risk of impact is lower, than in rings, where the protruding apex would be exposed to daily wear. When used in rings, a deep, well-fitted bezel or a custom cradle setting that supports the stone's full height is essential.

The height of the stone also affects the overall profile of the finished piece. A bullet cabochon of significant size will produce a ring of considerable elevation — a design choice that suits certain aesthetic traditions, including Arts and Crafts, Art Nouveau, and contemporary sculptural jewellery, but that may be impractical for everyday wear.

In the Trade

Bullet cabochons are not a staple of mass commercial production. Their demand for deep, high-quality rough, the skill required to maintain a symmetrical taper, and the lower yield relative to a standard cabochon all contribute to their relative scarcity in wholesale catalogues. They are most commonly encountered in the inventories of specialist lapidaries, at gem shows catering to designer jewellers, and in auction lots featuring notable asteriated or chatoyant stones where the cut has been chosen deliberately to maximise the gem's optical character.

When evaluating a bullet cabochon, the same criteria apply as for any cabochon: symmetry of the dome (assessed by rotating the stone under a single light source), centring of the optical phenomenon, quality of the base polish, and integrity of the apex. A well-cut bullet cabochon will show its star or eye precisely centred at the apex when the light source is directly overhead, with the phenomenon moving smoothly and without distortion as the angle changes.

Further Reading

• Gems & Gemology — GIA's peer-reviewed journal (gia.edu)
• GIA Gem Encyclopedia (gia.edu)
• Cabochon Cutting — International Gem Society (gemsociety.org)