Antique lamp shades date back to centuries ago when lanterns and even oil was being used. The other name for these lamp shades are called vintage shades. Most of the shades were 
known to be made of glass. These lamps shades obviously give that ancient look and the Victorian style is said to be one of the most popular in our times. The glass stained lamp shades looks awesome and give such a serene and peaceful appearance to the room when it is lit up that it makes a difference to the environment. Tiffany and Handel were the well known designers who are known for their glass lamp shades and Tiffany still has a great name in US.
Most of us love to have antique articles and lamp shades happen to be one of them. You can find them in a number of places such as homes, offices, art galleries, museums, hotels, restaurants, antique shops, clubs, pubs, casinos and so on.
If you want to restore your antique lamp shades, then one way to do it is to first check if the shades have any major damage like holes or if the frame is damaged. If the frame is mildly damaged, it can be set right with just a little fixing that can be done on your own. Anyhow, there are also antique specialists who can give their expert advice and do the job for a reasonable fee. If the shades are dull and dirty and needs some cleaning, this can be cleaned using a damp cloth. For shades that have a fabric material, this can be cleaned with mild detergent and warm water. If the shades are made up of paper, there are art gum erasers which helps make a huge difference. If the color is just white and has a dirty appearance, a dye can be used or bright color dyes can give it a new appearance. For shades that have silk material and needs cleaning, there are online websites that give you a number of tips on how to clean up such lamp shades.
To decorate your interiors, these antique lamp shades can be transformed to a great extent. All that is required are a few changes such as painting the lamp shades. Wallpapers can also be used to bring about a transformation, but once again it depends on the fabric. Adding extra stuff like mirrors, sand, shells, dried leaves, flowers can help decorate the lamp shades although you may not want to do that to a really nice piece. If however you have a damaged one, it can be made serviceable by doing this.
While purchasing these, you can choose the one that appeals to you most. If you are settling for buying glass shades, you need to check if the glass has any cracks or if it has been replaced. Make sure the base and the frame are intact with no flaws whatsoever. For shades that have fringes or other decorative stuff that has been added, you can probably double check to ensure they have a neat finish. Finally also take a look at the manufactures name. Always ensure the wiring is intact.
To shop for these antique lamp shades, one of the best places to search is on the Internet. Many online websites provide enough and more information on the antique shops where the lamp shades can be purchased without being cheated. The prices will vary depending on how old the piece is, obviously. Moreover the color, the design, the materials used, the popularity of the lamp shades will determine the pricing of the lamp shade. If you have really elegant interiors in your home a good antique lamp shade will set it off beautifully and if you feel that the real ones are too expensive, you can always go for the replicas which look quite good in their own right.
I have an old cast iron lamp both the shade and base have a green type of marble or glass not really sure. It was converted from a gas lamp trying to find out how I can see what is it worth.