The Elegance of Silvered Mercury Glass 

By Diane Lytwyn

Silvered mercury glass describes glass that was blown double-walled, then silvered between the layers with a solution containing silver nitrate in a liquid formula and sealed.

With its unique mirror surface and sleek silvery shine, mercury glass is easy to identify and is truly distinct among the many types of Art glass produced in the 19 century. While virtually silver in appearance and commonly referred to as "mercury glass," silvered glass has nothing to do with the precious metal, and mercury was never used in the formula for tableware.

Although blown glass orbs coated on the inside with mysterious liquid silvering solutions first appeared in the late 17th century, the decorative vases, beakers, goblets and tableware known today as mercury glass were first made around 1840 in the forests of Bohemia, which is now the Czech Republic. Appearing almost simultaneously in Bohemia, England and the United States, silvered glass created an instant sensation in the mid-19th century and was lauded as an important discovery in scientific journals.

Silvered glass was shown at the great Crystal Palace Exhibition held in London in 1851. The unusual beauty and novel techniques used to create the glass were praised in several essays from two prominent publications including, "The Illustrated Catalogue" by the Art Journal and in "Tallis's History and Description of the Crystal Palace", both of which provided lessons on taste by leading authorities of that time. Several years later, silvered glass made by the New England Glass Company was exhibited at the New York Crystal Palace held in 1853.

Initially a curiosity, silvered glass may have become popular because of its marked departure from the aesthetic tedium of the clear blown and pressed glass made in the early 19th century. Sometimes referred to as a novelty, the production of silvered mercury glass lasted about 80 years.

Although early figural pieces and simple vessels made in Bohemia may have provided a less expensive alternative to metal ware, the prevailing styles of mid-19th century coin silver or silver-plated items were in no way comparable to silvered glass forms and styles. Silvered glass was acquired and collected based on its unique and inherent artistic value as decorative glass, and not, as often thought, as a substitute for silver. In fact, silvered glass may rightly be considered the first true type of art glass.

The double-walled glass vessels used for silvering were made free-blown and involved the use of a hollow blowpipe and a long, flat-topped iron tool called a punty rod. After the piece was blown into it's final shape, the punty rod was attached to the other end of the object being worked to finish it. After the object was completed, it was cracked off the punty rod, and the remaining aperture was the route used to introduce the silvering solution.

Since the glass was blown, there is always a pontil "scar," which is the mark left after the glass is cracked off the punty rod during the finishing step. The presence of a pontil scar may be considered the hallmark of most blown glass, and in cases where the rough edges in this area were then polished or smoothed, a slight depression or other evidence is usually visible underfoot.

Created in a wide variety of shapes and styles, silvered mercury glass was crafted into beakers, compotes, curtain tie-backs, figures, gazing globes, goblets, pitchers, salts, tableware and vases. Many pieces were subject to an astonishing variety of decorating techniques, including hand painting, acid-vapor matting, enameling, etching, engraving, overlay casing cut to silver and even the application of glass "jewels." Mercury glass can be colorful and elegant or simple and austere, depending on the maker, and collectors may focus on a particular shape or decorative style.

For most collectors, mercury glass made in Bohemia is most often found since great quantities were produced there from about 1840 to at least 1920. Silvered glass was made in the United States for about 30 years, from approximately1851 to around 1880. The production of English silvered glass, however, lasted only about six years, from 1849 to 1855, and examples are difficult to find. Edward Varnish and Fredrick Hale Thomson of England were granted a joint patent for silvering glass, issued in 1849. These signed pieces are extremely rare, and therefore, highly sought after.

The discovery of a signed piece is unusual, as most silvered mercury glass is not marked in any way. In spite of not being marked, it is still possible to identify the country or origin by a careful examination of the piece. Attribution can often be established based on determining the type of glass used and the style of decoration. English and American pieces, made from flint glass or glass with lead in the formula, are quite heavy for their size, have thick walls, and a bell-tone resonance when tapped.

Bohemian items are generally lightweight by comparison. Bohemian glass items were made from glass that did not contain lead and were blown quite thin. Since the glass could not endure the cutting wheel for traditional engraving, the Bohemians developed many other decorating methods, including the granulate application technique.

Granulate application etching is the process whereby crushed or pulverized quartz crystal, acting like a powder, was applied to the prepared surface with the use of a design template or stencil. The piece was then re-fired on low heat to set the pattern. This decorating method is probably unique to silvered mercury glass, and a myriad of patterns ­ grapes, grape leaves, tendrils, flowers, ferns, palms, birds and motifs consistent with the Bohemian forest style typical of the late 18th and 19th centuries ­ are found most often. In addition, the gold wash effect on the interiors of the vast majority of compotes, beakers, goblets, pitchers, salts and vases were achieved with the use of chemical stains. The contrast of the gold to silver resulted in a piece of extraordinary brilliance. It is found on silvered glass made in Bohemia and on some English pieces, but silvered glass made in the United States, however, was never gold washed.

Bohemian silvered mercury glass is often found with bright enamel coloration and gold accents on a frosty satin ground. American glass was either plain or engraved, while English silvered glass pieces were cased and cut to silver. Cased glass refers to glass blown with a top overlay layer of transparent colored glass, which was then cut through to the clear or silver layer in a variety of geometric patterns. Cased silvered glass, which was made in England and rarely in other countries, is extremely rare to find.

While the differences in decorating techniques offer some assistance to establish attribution, the ultimate clue in the determination of the country of origin and, in some cases the maker, is found in the type of seal that was used.

Although not completely foolproof, mercury glass pieces from England were finished with an impressed metal disc covered by a glass wafer, which was cemented into the polished pontil scar. Many Bohemian items used lead or metal seals with glass discs, but the pontil was left rough, or sharp-edged. The Bohemian firm of Hugo Wolf did use a similar seal, and rare pieces with the "HW" embossed on a metal disc under glass can be found. The sealing methods utilized in the United States, by comparison, included the use of a simple cork in the rough pontil scar, or in the case of the New England Glass Company of Cambridge, Mass., a metal disc impressed with "NEG.Co." covered with a glass disc was used to seal the piece.

The ability to correctly identify the country of origin may be exciting for the collector, but it is the variety of shapes, styles and surface decorations found in silvered glass that compels acquisition and appeals to many tastes, ranging from formal art glass decorative to historical Americana and rustic country cottage.

The value of silvered mercury glass depends on its rarity, condition and quality of design. Beginning collectors may be able to find simple painted mercury glass vases, usually made in Bohemia and in average condition, for under $200. The engraved silvered flint glass made in the United States is more difficult to find and makes up the middle market, while cased or colored English silvered glass, marked "Varnish" or "Thomson", are rare to discover and may be priced in the hundreds if not thousands of dollars.

Silvered mercury glass items found with the original seal are usually higher priced than pieces with an open pontil scar, or hole, underfoot. Once the seal is opened or lost, the degree of silvering degradation depends on atmospheric conditions, and significant flake or patch loss greatly affects the value. Any chips, cracks or damage to the glass itself, as with other types of old glass, detracts considerably from appearance and price.

The appeal of antique silvered mercury glass has contributed to the development of new, mass-produced items available on today's market. One way to tell the difference is to examine the bottom. Silvered glass made in the 19th century will always have some type of seal or opening underfoot, while contemporary items are smoothed, much like the lining of a thermos bottle. By studying the traditional decorating methods used, mistakes can be avoided.

Silvered mercury glass is sold in antique shops, at shows and on-line. Be sure to examine pieces carefully for damage, and on Internet sites such as eBay, prospective bidders should always request a photograph of the bottom seal. Descriptions and photographic images can be deceiving, so ask about condition before you bid or buy.

The acquisition of fine pieces of silvered mercury glass can pose a challenge for collectors because surviving examples are not easy to find when compared to other types of art glass.

Perhaps it is the rarity of the glass itself that contributes to its allure, but the glittering beauty of this unique antique glass can offer real aesthetic pleasure to any collector, and investment in this art glass may well reward the willing, as values are sure to increase in years to come.

Diane C. Lytwyn is the author of the Pictorial Guide To Silvered Mercury Glass (Collector Books). A collector for years, Diane has lectured on the topic of mercury glass and has created the website www.antiquemercuryglass.com.
 

Gold washed, etched mercury glass made in Behemia,
circa 1860-80.

Group of painted enamel decorated vases, 1860-80. Top: Mint vivid enamel flowers on satin matte ground; right: gold butterfly and florals, hand painted and cold enamel; bottom: painted Parrot vase, bright color;
left: unusual lacy raised paste enamel and gold Victorian-style decorations.

Group of rare blown-molded Bohemian silvered glass pieces, circa 1860-80.

Left & Right: Naïve hand painted vases; center: bulbous vase, gold washed interior, some wear to
silvering. Bohemia, circa 1860-80.

Rare colored Bohemian mercury glass, circa 1860-80. Top: Satin matte ground and intaglio gold flashing engraved to silver;
right: satin matte ground with rare blue coloration banding; left: rare and traditional "forest" decoration, ruby casing cut to silver.