The subject of coasters should be rather simple and straightforward, but it isn’t.
Coasters prices do run the gambit for sure. Most of the prices are impacted by where the coaster is manufactured, the quantity, and from what type of material the coaster is made. Paper fiber coasters with generic designs it is probably the cheapest at 25¢ each. These are great for outdoor use. At the other end of the spectrum are stone coasters. Depending on the stone, they retail for about $30.00 per set. In between these ranges are where other coaster materials such as: silicone, cork, wood, ceramic, cloth, and glass.
A fiber coaster like used in most family or sports oriented restaurants is straight forward and is not part of this discussion. Then there are the cork coasters. Hard to believe but there are more than 3 types of cork and more than 5 grades. The low end of cork is the agglomerate corks which are nothing more than scrap pieces glued together under pressure. Synthetic is make from plastic materials. Finally there is the cork material used in such applications as wine bottles. Here is where it gets tricky; wine corks can also fall within 5 quality grades. So when looking at cork coasters they should be at least 3 mm thick and be made of non-agglomerated cork. Basically, glue does not absorb condensation or spills and just stay with good colored and non-porous cork.
I personally like the look and feel of bamboo. It is rich in tone and texture and like cork, it is sustainable material. Bamboo is now very popular as home flooring. Look for bamboo coasters that are made using multiple plies. This feature will keep the bamboo stable when it gets wet. Single ply bamboo coasters will warp when they get wet. Also look for bamboo that has been treated with a sealer such as Teak Oil or Danish Oil. This will present moisture from getting into the bamboo and prevent staining from beverages such s tea, coffee, wine, coke and fruit drinks. Also bamboo coasters can come in colors also. A major issue is that heavy condensation will cause the coaster to stick to the bottom of the glass.
Now we come to the discussion of stone coasters. Like bamboo, it is natural, elegant and can add a great accent touch to home décor. In a discussion with an interior designer, it was pointed out that stone is almost like a living thing that adds sophistication to a home. The trick as the designer points out is to get a stone that compliments the ambiance of the home. Currently there are four natural stones prominently used in coaster applications-sandstone, slate, travertine and polished stones (granite, marble). The first three absorb moisture from glasses and the later do not. Porous stones, if sold untreated, do allow moisture to penetrate through the stone. Secondly, natural stones are generally approximately 3/8 inch thick. This is a hefty coaster; however, it is very elegant. Granite and marble are not porous and when condensation is present it can be unsightly in certain entertaining environments to see puddles of water laying on the surface.
The best stone I have found is a solid surface stone made by using resins to hold quartz stone together. It is very stable, non-porous, stain resistant, ¼ inch thick and comes in very nice natural stone colors. In fact this type of stone has been used in a very high profile TV home makeover show. As an accent piece this is most elegant and with the myriad color options it is perfect for corporate boardrooms and contemporary home interiors.