The Grobet stone holder is a compact, spring-actuated hand tool used by lapidaries, bench jewellers, and gem setters to grip loose gemstones securely during inspection, photography, or light bench work. Manufactured by Grobet USA — the American successor to the Grobet File Company of Switzerland, a long-established supplier of precision hand tools to the jewellery and watchmaking trades — the holder operates on a simple spring-loaded claw mechanism that closes around a stone when released, holding it firmly without adhesive or wax. Its low cost and immediate availability through most jewellery-supply distributors have made it a standard accessory in the trade.

Design and Mechanism

The tool consists of a slender handle, typically of metal construction, terminating in a set of spring-tensioned jaws or claws. Squeezing the handle opens the jaws; releasing pressure allows the spring to close them around the girdle or pavilion of a stone. The claw geometry accommodates a range of stone sizes and shapes without adjustment, making it faster to deploy than a dop stick or adhesive-based holder. Most versions are small enough to be held like a pencil, allowing the jeweller to rotate and tilt the stone for examination under a loupe or microscope.

Applications

In everyday bench use, the Grobet stone holder is most valued for tasks that require brief, hands-free or single-handed control of a loose stone:

• Visual inspection and grading under magnification
• Presenting a stone to a client or colleague for viewing
• Positioning a stone adjacent to a setting prior to final placement
• Minor cleaning or surface examination without risk of skin oils contaminating the facets

It is not intended for the sustained, vibration-resistant grip required during faceting or cabochon cutting, where dop sticks — bonded with wax or epoxy and mounted in a faceting machine — provide the necessary rigidity and angular repeatability. Vacuum chucks offer a comparable advantage for precision work. The Grobet holder occupies a different niche: speed and convenience over precision.

Limitations

Because the claw contacts the stone at the girdle or pavilion, there is a small risk of surface abrasion on very soft materials (below approximately Mohs 6) if the jaws are metallic and the stone is manipulated under pressure. For fragile or included stones, some practitioners prefer a wooden dop stick with a minimal wax bond, or a purpose-made rubber-tipped holder, to reduce contact stress. The spring tension, while generally gentle, is fixed and cannot be adjusted for exceptionally small or large stones beyond the tool's rated range.

In the Trade

The Grobet name carries broad recognition in North American and European jewellery supply channels, partly because the parent company's files, gravers, and precision tools have been in continuous professional use for well over a century. The stone holder is typically stocked alongside other Grobet bench accessories and is considered a disposable or low-investment item rather than a precision instrument. It is often purchased in small quantities as a convenience tool and replaced when the spring loses tension or the jaws show wear.