I have found a few in the past that actually said Nickel silver.
I am going with the Nickel/silver.
a quote
Nickel silver is a metal sometimes used in the making of costume jewelry. Although it is called silver, it doesn’t actually contain any silver in its composition. The word ‘silver’ in this case refers to the color of the metal rather than the content. Because of this, nickel silver often causes confusion to buyers, who may think that it’s a silver alloy.