About Mirror Work :-
mirror-work, is a type of embroidery which attaches small pieces of mirrors reflect metal to fabric. Mirror embroidery is spread throughout Asia, and today can be found in the traditional embroidery of Iran, India, Pakistan, Afghanistan, China, and Indonesia.
Mirrors have always been women’s favorite and the same applies to the work on sarees too.
For more info : http://www.g3sarees.com/mirror-work-saree.html