This article was originally published as an 'Expert Advice' column in the June 2011 issue of Bead & Button. Some revisions, photos and further explanations have been made here.
Handmade lampwork beads, made by an ever-growing community of people working in their home studios, are quite popular in today’s jewelry designs, but do all of those odd words people use to describe them just confuse you? The next time you hear someone say ‘Look at that shiny design- is that fumed or did they use silver foil?’ don’t just smile and nod; pull out this handy glossary and say ‘I think I see a bit of dichro encased in there!’
If you are a purchaser of lampwork beads, you may also find this article of interest.
Techniques and Basics
Annealing- Cooling a bead slowly in a kiln to equalize the temperature of the glass. This relieves stress, which keeps cracks from forming; even a small crack in a bead can grow, eventually causing it to break.
Some small beads are cooled in a fiber blanket, annealing bubbles or vermiculite though annealing in a kiln is preferred. Lampworkers should specify the cooling method used.
Encasing (overwrapping)- A covering of transparent glass that will magnify the pattern in the core bead. The best encased beads will not contain unintentional bubbles, though many do. These bubbles do not hurt the integrity of the glass.
Fuming- Flame-Vaporized silver or gold thinly coats a bead; the metallic ‘fumes’ are deposited on the bead.
Hollow Bead – Two parallel disks of glass are wound on a mandrel and sealed together to form thin- walled, lighter weight bead.
Imploding- A series of dots placed inside a hollow tube are encased and elongated, creating the appearance of an explosion inside the piece. An ‘inside-out’ design most often associated with boro glass.
Lampworking (flameworking)- Melting and working glass over an open flame.
Masking- Melting and overlapping dots to make a design which becomes more complex with each additional layer.
Puckered ends- Indented holes at the end of the bead. Beads should never have sharp holes; these can chip or cut through beading cord.
Raking- Dragging a tool across lines or dots on the surface of the glass creates a zigzag or elongated pattern. Similar techniques are furrowing, feathering and combing.
Plunging- Trapping air bubbles by poking a divot into the bead and encasing with transparent glass.
Trail (stripe)- A line drawn on a bead.
Cane- Any glass rod, especially a handmade rod of layered colors, often used for plant stems and leaves.
Devitrification (devit)- A powdery looking glass surface that develops on some glass.
Dichroic Glass (dichro)- Glass coated with a thin metallic film, causing the color to shift depending on the angle and light in which it is viewed.
EDP- Evil devitrifying purple, a color prone to devitrification.
Enamel- Powered glass pigment used to add a thin layer of vivid color; mica and pixie dust are also used in this way.
Frit- Small bits of broken glass; a hot bead rolled through frit picks up pieces as it goes. ‘Raku’ frit can turn many different colors.
Metals- Silver, Gold, Palladium or Copper may be used as a core, to coat a bead, or to create different colors and designs; comes in the form of foil, leaf, wire or screen.
Murrini or millefiori- A thinly sliced tube of glass with a design in cross section. Millefiori has a floral design; other designs are referred to as murrini.
Reduction or striking glass (reactive glass)- Shines or changes color depending on the heat and amount of oxygen used in the flame. Also known as reactive glass.
Shards- Small pieces of thinly blown glass used to apply color and texture to the outside of a bead.
Silvered Ivory Stringer (SIS)- Stringer made from ivory glass rolled in silver.
Stringer- A thin rod of glass often used for drawing on a bead.
Twistie or latticino- Different colors of glass are layered and twisted together. These can be anything from a simple two color twist to very complicated lacy designs.
Types of Glass
Borosilicate glass (boro)- Hard glass; a type of pyrex used to make beads, pendants, and sculptures.
Soda Lime Glass- Soft glass, used for most lampwork beads. The type of glass used will vary depending on colors, effects and COE desired.
Bullseye and Spectrum- Produced in the U.S., COE 90 and 96
CIM (Messy Glass)- Produced in China.
Devardi Glass- Produced in India.
Double Helix, Rocio and TAG- Specialty glass made in the U.S. Most of this is reactive glass.
Gaffer- Produced in New Zealand.
Kugler, Lauscha or Reichenbach- Produced in Germany.
Murano Glass- Made on the Italian island of Murano. Effetre (Moretti) and Vetrofond are produced in Murano or Venice.
Chill marks- Concentric circles left after a cool tool touches the glass, causing stress on the glass surface, usually ‘fire polished’ out over the flame. Minor chill marks are infrequently used as design elements.
COE- Coefficient of Expansion. A number describing how quickly glass expands and contracts. COE determines whether the glass is ‘soft’ or ‘hard’. Generally, glass used in the same piece will have the same COE, though sometimes small accent bits with a different COE may be used safely.
Cold Working- Any procedure done while the glass is cold, such as electroforming or using a lapidary wheel.
Mandrel- The steel rod on which a bead is built which determines the size of the bead’s hole. The bead release or ‘sludge’ used to keep the glass from sticking to the mandrel should be removed from all beads.
Tool Marks- Marks left on beads from tools. Sometimes, as in the case of fish fins, tool marks are used decoratively.
Wonky- Uneven or out of round.
Bead shows, galleries, gift shops, even farmer’s markets are great places to see the work of your local lampwork artisans up close; online choices include personal websites, faccebook, etsy, artfire and ebay. The best indicator of the quality of a bead maker’s work beyond the photos or handling the beads yourself is their description of the techniques, cooling process and materials used.