The first coasters were designed for decanters or wine bottles, so that they could be slid (or "coasted") around the dinner table after the servants had retired.  The Victorians would also use coasters for drinking glasses, these were most commonly made from silver plate or silver plate and wooden bases.
 
This is a decanter coaster with silver plated pierce-work sides and a turned oak base, protected by a green felt cushions. Would have been used in a reasonably wealthy household.
 
 In good polished condition.
 
Dimensions: 13cm diameter