Sulphides: Ceramic Cameo Inclusions in Glass
Sulphides are decorative glass objects containing embedded white or silvery ceramic cameo figures, portraits, or designs encased within clear glass. The technique, developed in Bohemia and France in the late 18th century and perfected by Apsley Pellatt in England around 1819, involves inserting a molded ceramic paste (china clay and potash) figure into molten glass without cracking either material. The name derives from an early misconception that the inclusions were silver sulfide. Sulphides appear in paperweights, tumblers, decanters, pendants, plaques, and marbles.
Identification & History
The technique requires precise temperature matching between the ceramic inclusion and the surrounding glass. Apsley Pellatt patented his "cameo incrustations" process in 1819 and published details in his 1849 book "Curiosities of Glassmaking." French glasshouses, particularly Baccarat, Saint-Louis, and Clichy, produced magnificent sulphide paperweights from the 1840s-1860s. American glasshouses, including the New England Glass Company, produced sulphides from the 1850s onward. The ceramic figures are typically white or silvery in appearance and may depict historical portraits, religious figures, animals, coats of arms, or commemorative subjects.
Types & Forms
- Paperweights: The most collectible form, with sulphide portraits set in clear glass, often with colored glass overlays or millefiori surrounds
- Tumblers & Goblets: Drinking vessels with embedded cameo portraits or decorative motifs
- Decanters & Bottles: Wine decanters and perfume bottles with sulphide inclusions
- Plaques & Medallions: Flat or slightly domed display pieces with portrait subjects
- Marbles: Handmade glass marbles with small sulphide animal or human figures
- Pendants & Jewelry: Small-scale sulphide inclusions mounted as personal ornaments
Auction Price Ranges
| Item | Price Range |
|---|---|
| Sulphide marbles (common animals) | $50 - $200 |
| Sulphide marbles (rare figures) | $300 - $2,000+ |
| American sulphide tumblers | $100 - $500 |
| Pellatt cameo incrustations | $200 - $1,500 |
| French sulphide paperweights (common) | $300 - $1,000 |
| Baccarat sulphide weights (portrait) | $1,000 - $5,000 |
| Baccarat overlay sulphide weights | $3,000 - $15,000 |
| Saint-Louis sulphide weights | $1,000 - $8,000 |
| Rare subject/double-overlay weights | $5,000 - $50,000+ |
Condition Factors
The ceramic inclusion should be well-centered and free of air bubbles or silvery hazing around its edges, though some degree of silvering is typical and even expected. Chips or scratches to the glass surface diminish value, especially on paperweights where optical clarity is essential. Cracks radiating from the inclusion indicate thermal stress during manufacture and reduce value. The detail and crispness of the ceramic figure affect desirability; well-molded, sharp portraits outperform crude or indistinct examples. Paperweights should retain original polished surfaces without re-grinding or re-polishing, which reduces diameter and value.
Collecting Tips
French paperweight sulphides from the classic period (1845-1860) represent the pinnacle of the art and command the highest prices. Baccarat examples are the most sought-after, followed by Saint-Louis and Clichy. Portrait subjects of historical significance (Napoleon, Queen Victoria, Benjamin Franklin) outperform generic or anonymous figures. Overlay sulphides, where colored glass layers are cut with windows revealing the inclusion, are particularly prized. Sulphide marbles are an accessible entry point for new collectors. Authentication requires examining the ceramic paste composition and glass quality; modern reproductions from China use different materials visible under magnification. The Bergstrom-Mahler Museum in Neenah, Wisconsin, holds a world-class reference collection.