Is there any difference between the Black container Mercury High Performance Gear Lube and the Grey container Quicksilver high performance gear lube?

Same stuff. The Quicksilver label is more for the West Marine type stores. As was told to me by a Merc dealer. Both are Mercury Marine

same stuff

Nope

Ok thanks,
Did not want to mix two different types but I thought they were the same.

Have been using the Merc type but have a bottle of the Quicksilver on the shelf and want to use to add a little.

Good question though.........I once questioned that myself.........

Did you know where the word "mercury" was derived from??

Mercury god
Mercury \Mer"cu*ry\, n. [L. Mercurius; akin to merx wares.] 1. (Rom. Myth.) A Latin god of commerce, thieves and gain ; -- treated by the poets as identical with the Greek Hermes,messenger of the gods, conductor of souls to the lower world, and god of eloquence.