It is NOT a matrix effect. Matrix is a trick (by Al Schneider) whereby the coins are apparently unable to be touched by the magician because there are four cards on top... and yet they gather one at a time beneath one of the cards.
Not all coin assemblies are matrix effects. 'Specially not Shade.
Shade is (for lack of a better word) a bastardization of Chink-a-chink, which is a type of coin assembly that used to be done with dice.
Also, it's not Kenner's Shadow Coins. I believe "Shadow Coins" is an effect named thusly by Michael Ammar. It is older than the hills, and is simply a cleaner (?) variation of Chink-a-chink.
Scott.