Examine the small mosaic in its gilded frame. From a distance, it looks like an oil painting. In fact, it's made of thousands of glass tiles, some no larger than the head of a pin.
The process of decorating glass by the use of gold leaf, gold paint, or gold dust. The gilding can be applied with size, or amalgamated with mercury. It is then usually attached to the glass by heat. Gold leaf can be picked up on a gather of hot glass.
![St. Peter's Square (family) [electronic resource] / Corning Museum of Glass.](http://d3seu6qyu1a8jw.cloudfront.net/sites/default/files/styles/1_column_square/public/images/no-image.jpg?itok=xFnyxjIk "St. Peter's Square (family) [electronic resource] / Corning Museum of Glass."){kind=small}
