The timeless appeal of crystal is a story of dichotomy, where sharp meets soft, fragile flirts with tough and traditional plays with contemporary. It’s those relationships, beautiful but fraught with opposition, that has secured crystal’s place among our most enduring materials.
The name crystal, which actually refers to lead glass, is a derivative of cristallo, the Italian word for Venetian glass that resembles rock crystal. It’s also a misnomer, as crystal contains no crystal structure in its composition, but rather tight, amorphous bonds that make it stronger than plain glass. Its durability, sparkling brilliance and ability to withstand cuts and engravings without cracking make it ideally suited for jewelry, glassware, ornaments, decorative pieces, enamels and lacquers, as well as optical lenses, radiation shielding and other industrial applications.
Lead glass has its roots in ancient Mesopotamia, the birthplace of the glass industry, with the earliest known example – a blue shard from Nippur – dating back to 1,400 B.C. The shard’s extremely low lead content, however, suggests that the element wasn’t yet intentionally being added to glass.
It’s believed that lead glass was brought to China during the Han dynasty (206 B.C. to 220 A.D.) by Middle Eastern glassworkers via the Silk Road. There, it was used to imitate jade for figurines, vessels and jewelry. In medieval and early modern Europe, lead glass was also used to imitate precious stones, as well as for glassware and enameling.
Glass as a modern industry originated in 13th century Venice, Italy, where many artisans fled to escape the Fourth Crusade in Constantinople. After the Dark Ages, Venice became the center of glass working, and it was here that cristallo was developed. The Venetians were pioneers of the glass industry. Biblioteca Marciana, a preserved Venetian manuscript, documents recipes for calcining lead to form lead oxide, the substance that turns plain glass to crystal. Around 1291, the glass industry was moved to the island of Murano over fear that the rapidly growing number of mainland refineries would cause a fire. The island was the center for glass for centuries to follow, and many of the techniques, designs and materials developed there are still in use today.
Around the mid-1500s, many of the leading Venetian glassblowers relocated to London, where they – and their trade – fell into favor with Queen Elizabeth I. Her promotion of their art form lead to a surge in its popularity, and the glass working industry spread throughout Europe.
In 1674, George Ravenscroft – who had close ties to Venice – set out to capitalize on the growing demand for lead glass, and obtained a patent to be its sole manufacturer in England. By 1676, his experimentations had refined the production of ‘flint glass’ (or lead glass). Ravenscroft’s perfection of the manufacturing process set the basis for England to overtake Venice as the center of the glass industry in the 18th and 19th centuries.
By the end of the 18th century, the lead-crystal glass industry was thriving in France, Hungary, Germany and Norway; by the 1800s, glasshouses like Baccarat in France, Orrefors in Sweden, and Swarovski in Austria became some of the world’s leading lead crystal manufacturers. However, until this point, most people could only afford pewter or wood drink ware. It wasn’t until mass production techniques were developed in the early 1800s that glassware became abundant and affordable.
While many pieces are made with molds, the traditional method for creating crystal products is glassblowing. The process is over 2,000 years old and has changed very little in that time. The raw materials of silica-sand, soda ash, limestone and lead-oxide have also remained unaltered.
Step 1 The chemical cocktail is mixed and turned into molten crystal in a 2,192° F furnace.
Step 2 Glass blowers (a.k.a. gaffers) dip a four-foot long hollow iron pipe into the melt and roll a small amount of molten glass (gather) on the end.
Step 3 The gaffer rolls the gather against a paddle or metal plate to give it an initial shape (marvering).
Step 4 The gaffer blows into the pipe to create a bubble (parison), using physical strength, steady breath, and dexterity to control the thickness and shape. The gaffer may reheat the parison at the furnace several times to create the final form.
Step 5 Once the main form is done, additional gathers may be applied to form stems, handles and other decorative additions. This step must be done quickly, as the glass hardens immediately in open air. At this point, the hot piece of glassware can be dipped into molten glass of a contrasting color (flashed).
Step 6 The gather is attached opposite the blowpipe to a solid iron rod called a pontil. Once the blowpipe is broken free, the gaffer shapes and polishes the open end. The pontil is then broken off and the rough spot that is left is removed with grinding and polishing. The piece is left to cool.
Step 7 The cooled piece can now be cut. A pattern is drawn on the vessel and roughed out with a power-driven wheel using different cuts. It’s then smoothed with a sandstone wheel to establish the finished design.
Step 8: Finally, the object is dipped into an acid bath that removes a very thin layer of the entire surface, leaving a lustrous, uniform finish.
Distinguishing Crystal from Glass
The introduction of lead-oxide turns plain glass into crystal. Lead also reduces the working temperature of the material, making it easier to sculpt, and altering the chemical structure to form a durable product that can be etched and cut without cracking.
How to tell crystal from plain glass:
- Clarity: While glass can be cloudy and opaque, crystal is known for its clarity. This very characteristic is what makes it a favorite of wine aficionados, who want to better appreciate their wine’s color and viscosity.
- Refraction: Crystal’s unique molecular structure gives it brilliant sparkle and makes it highly refractive. When held into the light, crystal acts like a prism and casts a rainbow; glass does not.
- Cuts: Crystal allows for a more precise cut and polish, making its facets smoother, cleaner and rounder than the sharper cuts of plain glass.
- Weight: Due to its lead content, crystal is naturally heavier than glass. Crystal feels solid, whereas glass is lightweight in comparison.
- Sound: When lightly struck, crystal makes a ringing noise in contrast to glass’ thud. Similarly, if you wet your finger and run it along the rim of a crystal glass, it produces a musical tone.
- Thickness: Crystal can be worked much thinner than glass; an exceptionally thin rim nearly always signifies crystal.
Lead vs. Lead-Free
In recent years, researchers have found that lead from crystal can leach into food and liquids. For this reason, many modern manufacturers of crystal glassware, decanters and other vessels have moved to lead-free crystal, in which zinc oxide, potassium oxide, or barium oxide are substituted for lead. The end result is a product that is just as durable and stunning, without the health risks. Typically, lead-free crystal is lighter than lead crystal (and, some might argue, slightly less refractive).
Crystal has seen an impressive array of applications over its many years, from the strictly utilitarian to the purely ornamental. But it’s both the versatility and humankind’s centuries-long love affair with the material that ensures new uses, decorative and otherwise, will always be dreamt up to honor crystal’s enduring and universal appeal.