Lighting Glass Types
Learn about the quality & style of glass.
Genuine Alabaster, in its pure form, is a mineral: a crystalline form of gypsum. The alabaster quarried is actually a rock frequently mixed with traces of other elements like iron which makes the dark veining or quartz.
There are three main types of alabaster: Opaque, chalky variety that is ground up and used in gypsum or plaster; Semi-transparent called the escaglione and Translucent used for alabaster shades and fixtures. The rocks, which are white with random amounts of translucent and mostly gray-brown veining when used for lighting, are from Spain.
Quarrying alabaster is costly and there is a huge amount of waste making it expensive. It is a relatively delicate stone and usable chunks of alabaster are mined from deep underground. Artisans working with the "Corazon" or heart of the raw rock, turn pieces of the alabaster on a lathe to create the desired shape and then carefully finish and polish the soft stone. The larger the piece, the greater the waste.
Genuine alabaster or imitation? When you see the genuine alabaster in person, you'll know it. Nothing glows like genuine alabaster. Other things to look for are thickness, weight and veining. Genuine alabaster is a minimum of 3/8 inches thick and weighs at least twice as much as imitations. Veins are both translucent and dark and are completely random. If you see two pieces that have the same veining pattern in the same location, they are not genuine.
Clean your alabaster fixture according to the manufacturers' instructions. It is a soft stone, so treat it gently. Generally, never use detergents or abrasives because alabaster is porous and both will damage it. Instead, wipe the stone with a slightly damp (not wet) soft cloth.
Tip: Alabaster is extremely heat sensitive. Once the stone reaches a temperature of 187 degrees, the water (the H2O part) in the crystal begins to evaporate. When purchasing an alabaster lamp, make sure there is a shield in the incandescent or halogen fixture to disperse the heat and protect the alabaster from heat discoloration.
Leaded Glass also known as art glass or Tiffany glass. This refers to the production of panels or windows made up of pieces of glass held together by strips of lead or lead-free alloy called "cames" which are grooved on each side to hold the glass together. Glass is joined by using a combination of copper foil on the edges of the pieces and solder. Each piece of glass is individually selected for its color, translucency and how it relates to the design. It is then cut to perfection, wrapped in copper foil, soldered and assembled by hand. All shades are then double-beaded inside and out to strengthen construction.
The metallic elements are then brought to a rich authentic bronze patina by coating them with a special solution. Finally the shade is hand-waxed to create a protective surface and lustrous finish. A leaded glass panel may incorporate simple clear flat glass or a variety of types of glass may be used to create patterns and images. Beveled glass may be incorporated in leaded designs as well. A single shade or window panel may incorporate several glass working techniques and up to several thousand individual pieces of glass. Brass cames may also be used but it is discouraged in a coastal environment due to the prevalence of corrosion.
Tiffany-style art glass vs regular glass shades. Every shade that is Tiffany-style art glass is made from glass and not plastic. Only genuine hand-rolled art glass is used in the making of this style of shade. This glass is manufactured the same exact way since the turn of the century and used by Louis Comfort Tiffany in his original designs. Each hand-cut piece of glass is wrapped in a thin slice of copper foil (copper foil technique) and then each wrapped piece is soldered together to build the shade. The fact that each piece of glass is wrapped in copper and soldered together deadens the sound when you touch it. There is no ping that you think it should have. The test is to take a coin or a piece of metal and tap the glass; you will then know it is real glass. Or, try the scratch test. Plastic will scratch easily, glass will not. These individual pieces of glass are cut from a four foot by four foot sheet and they will shatter. Also, this art glass tends to be fairly thick, which happens when you mix a lot of colors together, this also adds to the deadening sound versus thinner glass which has a greater ping when tapped.
Stained Glass. This term is usually used to apply to anything made of leaded glass that incorporates colors and patterns. This is not precisely correct. Colors and patterns may be created using glass in a variety of ways, beginning with the pigmentation of the glass during its manufacture such as transparent red and blue. The addition of white glass to a colored glass during manufacturing produces a semitransparent or opalescent glass. Texture may also be imparted to a sheet of glass when the molten glass is pressed through rollers (rolled glass). Glass may also be enhanced by painting the surface with pigments mixed with powdered glass which are then bonded together in a kiln for a permanent image. Additionally, silver stain may be used to give glass a yellowish tint; this process is called stained glass.