Not to be contrary, but silver is pretty common. It is often found in Murano glass, as well as glass from Bohemia, USA, China, and other places. It is especially common in the tutti frutti pieces.
I understand what your friend means. I've seen more Murano speckled with gold dust than I have with silver. I imagine that with the cost of gold being so high right now, gold is being used much more conservatively.