Sterling silver
Pure silver is beautiful and far too soft to hold a shape, so it is always alloyed for strength. Ours is alloyed with zinc, with less copper than conventional sterling, and carries a silver content above the 925 standard rather than merely meeting it.
That is deliberate. Copper is the element chiefly responsible for the darkening most people associate with silver. Leaning on zinc instead means the metal holds its brightness longer in humid, coastal and polluted air, which describes most Indian cities for most of the year.