Mica: A Unique Material
Mica is the name of a mineral composed of silicon and a variety of other substances such as sodium, calcium, aluminum and magnesium amongst others. Its overall color is sandy to brownish. One of its basal properties is a glittery look when struck by light. Mica is an interesting mineral in that it can be cleaved naturally to form planar surfaces, or sheets. However, most of the industrial material that is used today is formed by bonding flakes of raw mica with other substances such as shellac and resin.
This allows the production of sheets that can come in different shapes, such as cylinders or planes of varying sizes. The important fact is that these shapes can be exploited for make lamp shades. The thin sheets allow some light to penetrate. Its mineral-like, glittery qualities make it an interesting shade that is reminiscent of glass shades but with a much more natural look.
Uses of Mica
Mica is actually used in electronics to make components such as capacitors and insulators. Although in the past it was a rare mineral, relatively recent finds of large deposits mean that it's become a cheap and common commodity. In addition to electronics, it is also being used for manufacture of lamp shades as mentioned already. In fact, it has been used for creation of artwork by humans for many tens of thousands of years. Therefore its use as an element of decor is not surprising.
Mica Lamp Shades
Mica lamp shades actually have been in use for most of the 20th century, dating back to the times when electric lamps first appeared. The fact that mica lamp shades are usually a raw, composite material and bonding resins means that it was inappropriate or even hazardous for use in gas lamps that predate electric lamps. However, electric bulbs have sufficiently good confinement of heat that shades became possible. In general, sheets are held in place by a metal frame much as standard glass lamp shades are constructed. In addition, cylindrical shapes can be made almost entirely from mica except for the top and bottom ring frame.
The Visual Quality of Mica
In fact, the look is quite diverse among lamp shades. The raw mineral has a narrow range of hues and reflective properties, but the manufacturing process of industrial material means that there is much greater variability in the colors and transmittance as well as reflectance of light. Some mica lamp shades are very pale bordering on being white whereas others are deep, rich browns. The composite nature of random flakes means also that no two shades will be truly identical. This is a unique feature that is not usually found in other kinds of lamp shades.
Styles of Mica Lamp Shades
There are perhaps a few basic shapes that can be found. The pyramidal look characterized by four sheets on four sides is a common kind of shade. The cylindrical and the cone lamp shades are two other common kinds. More exotic shapes are limited by what the artisan or factory is able to do with this relatively fragile material. Aside from standard standing or table lamps, mica lamp shades are also found as part of chandeliers. For chandeliers, there is a little shade for each bulb composed of the material. Unique Tiffany-style mica lamp shades can also be found, which are essentially shades with interesting ornate mica shapes embedded in the frame.
The distinctive uneven sand or brown color of this material is replicated partly with modern plastic materials which cost far less to buy and replace. Some lighting stores carry the plastic version but advertise it as being the real thing. Check the shade yourself either by asking, via the photo or in real life at the store. Now it is possible that the plastic is actually a resin mixed with powder so technically so technically it is mica. But the processed material is inferior to the real thing so expect to pay less and get less aesthetics out of it.