Silver has properties that make it unique and irreplaceable for industry. Nothing else combines strength with a softness that allows it to be formed and stretched. Nothing conducts electricity as well or is malleable, fatigue resistant, wettable and corrosion resistant. Nothing else has such high tensile strength, is wear resistant, has such a long functional life or is as light sensitive. It endures temperature extremes, conducts heat, reflects light, provides catalytic action, is bactericidal and reduces friction. It alloys and has chemical stability. From this you can see that silver can’t be substituted. It has too many unique properties.