The golden thread used in a Kerala saree, also known as the Kasavu saree, is typically made from a metal called Zari. Zari is a type of thread that is woven with a metal core, usually made of silver or gold, and is commonly used in traditional Indian textiles to add sparkle and shine to clothing and accessories.
The golden zari thread used in the border of the Kasavu saree is woven into intricate designs that can vary from simple stripes to more elaborate patterns. The golden border of the saree is considered a symbol of wealth and prosperity, and is an essential part of the traditional design.
In recent years, modern variations of the Kasavu saree have emerged that use other types of metallic threads, such as silver, in addition to or instead of the traditional golden zari. Despite these changes, the golden border remains a key element of the Kasavu saree, and is a cherished part of the cultural heritage of Kerala.