A hollow cabochon is a cabochon-cut gemstone or ornamental material in which the pavilion — the underside of the stone — has been ground or carved into a concave, bowl-like form rather than left flat or convex in the conventional manner. The crown retains the characteristic smooth dome of any cabochon, preserving the stone's visual identity, while the hollowed interior reduces overall weight and the volume of material consumed. When the concavity is particularly pronounced and deliberately shaped, the form is sometimes referred to by the French term chevée, a word with historical currency in the French jewellery trade. The hollow cabochon is most commonly encountered in opaque and semi-opaque materials — turquoise, coral, onyx, malachite, and lapis lazuli among them — though it is occasionally applied to translucent stones where weight reduction or a lighter setting profile is desirable.

Construction and Geometry

In a standard flat-base cabochon, the pavilion is ground to a level plane perpendicular to the girdle, providing a stable surface for bezel or prong setting. In a hollow cabochon, this plane is replaced by a concave depression that may range from a shallow dish to a deep hemispherical cavity. The girdle — the narrow band at the widest circumference — remains intact and serves as the structural perimeter. The crown profile is unaffected by the pavilion treatment and may be high-domed, medium-domed, or low, depending on the cutter's intention and the optical character of the material.

The degree of hollowing is constrained by the thickness of the girdle wall: too aggressive a removal risks fracturing the stone at its thinnest point, particularly in brittle materials such as coral or turquoise. Skilled lapidaries therefore calibrate the depth of the concavity to the hardness, toughness, and cleavage characteristics of the specific material. In practice, the hollow is most often produced on a small grinding wheel or a spherical burr, with the stone held in a dop and rotated against the abrasive surface.

The Chevée Form

The term chevée (occasionally spelled cheveé in older English-language texts) derives from French jewellery vocabulary and designates a hollow cabochon in which the concavity is deep enough to constitute a meaningful interior space. Historically, the chevée construction was used in French and Swiss watchmaking and jewellery of the eighteenth and nineteenth centuries, particularly for enamel work and for stones set into brooches and châtelaines where minimising total weight was a practical concern. The term is rarely used in contemporary English-language gemmological literature, but it persists in auction-house catalogues describing antique French pieces and in specialist texts on historical jewellery techniques.

Materials and Applications

The hollow cabochon is most prevalent in the following material categories:

• Turquoise: Natural turquoise of high quality is relatively rare and commands significant value by weight. Hollowing the pavilion of a large turquoise cabochon reduces material cost while maintaining the full face-up appearance of the stone. This practice is well established in both Native American silversmithing traditions and in European fine jewellery.
• Coral: Precious coral (Corallium rubrum and related species) is an organic material subject to international trade restrictions and therefore of considerable per-gram value. Hollow cabochons allow larger apparent stones to be produced from limited raw material.
• Onyx and chalcedony: Black onyx, carnelian, and other dyed or natural chalcedony varieties are frequently cut as hollow cabochons for use in signet rings, cufflinks, and mourning jewellery, where a large, flat-faced oval or round is aesthetically required but weight in the finished piece is a secondary concern.
• Malachite and lapis lazuli: Both materials are dense and relatively abundant, but hollow cutting is used when large statement pieces are required and overall weight in a brooch or pendant must be kept manageable.
• Translucent and transparent stones: Less commonly, hollow cabochons are produced in rose quartz, moonstone, or even lower-grade corundum, where the concave pavilion can create an unusual optical effect — a softening or diffusion of transmitted light — and where a lighter finished piece is preferred for wearability.

Gemmological and Trade Considerations

From a gemmological standpoint, the hollow cabochon presents specific challenges in valuation and disclosure. Because the concave pavilion is concealed within a bezel or closed-back setting, a buyer examining a mounted stone cannot readily determine whether the pavilion is solid or hollow without removing the stone from its setting. This is commercially significant: a hollow turquoise cabochon of, say, 15 mm diameter may weigh considerably less than a solid example of identical face dimensions, and its intrinsic material value is proportionally lower.

Reputable laboratories and dealers are expected to disclose hollow construction when it is known or detectable. The Gemmological Institute of America's grading reports for coloured stones note the overall weight of the submitted stone; a hollow cabochon will register an anomalously low weight relative to its face dimensions, which an experienced grader will flag. In the trade, the practice of hollowing is not considered a treatment in the same category as fracture filling or heat enhancement — it is a cutting decision — but it is nonetheless a material fact that affects value and should be disclosed.

Detection of hollow construction in a mounted stone may be accomplished by several means: weighing the piece and comparing the result against the calculated weight for a solid stone of the same dimensions and specific gravity; transillumination, which may reveal the thinner walls of a hollow pavilion in translucent materials; and, where access permits, direct visual inspection of the pavilion through the setting aperture or after removal from the mount.

Historical Context

The practice of hollowing the backs of cabochons has a long history in jewellery-making. Archaeological evidence from ancient Egyptian and Roman jewellery indicates that large gemstones and paste imitations were sometimes backed with foil and set in closed settings that effectively concealed any pavilion treatment. The deliberate hollowing of the pavilion as a weight-reduction technique became more systematised during the Renaissance and Baroque periods, when large ornamental stones in elaborate gold mounts were fashionable and the economics of precious material were closely managed by court jewellers. By the nineteenth century, the technique was sufficiently codified in the French trade to have acquired the specific term chevée.

In the Arts and Crafts and Art Nouveau movements, hollow cabochons in turquoise, moonstone, and opal were used extensively, partly for their practical advantages and partly because the shallow, domed form suited the organic, low-relief aesthetic of those periods. Many surviving pieces from makers associated with those movements — including work retailed through Liberty of London — incorporate hollow cabochons that are identifiable only upon removal from their original settings.

Further Reading

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