Ductility
Ductility can be quantified by the fracture strain formula_1, which is the engineering strain at which a test specimen fractures during a uniaxial tensile test. Another commonly used measure is the reduction of area at fracture formula_2. The ductility of steel varies depending on the alloying constituents. Increasing the levels of carbon decreases ductility. Many plastics and amorphous solids, such as Play-Doh, are also malleable.
The most ductile metal is platinum and the most malleable metal is gold.
Zari
In ancient times, when precious metals were cheaply and easily available, only real zari threads were produced. Due to industrial revolution and invention of electroplating process, imitation techniques came into existence to cut the cost of precious metals. As copper is the most malleable and ductile metal after gold and silver, silver electroplated copper wire replaced pure silver. Various modern colours and chemicals are used to create/impart a golden hue instead of pure gold. The precious metals and copper too became dearer due to huge demand in various modern industries. Thus, a cheap and durable alternative was invented with non-tarnishing properties. Metallic zari came into vogue replacing traditional metals like gold, silver & copper. This non-genuine modern zari is light in weight & more durable than earlier editions. Also, it has the sought after properties of resistance to tarnishing and knotting.