Yttrian andradite is a common accessory mineral in granite pegmatites from the southern Gatineau Park, Quebec. Samples from three separate occurrences showed 2.65, 1.23, and 0.74 percent yttrium. These garnets are unusual in being virtually the sole rare earth minerals in the pegmatites and in their lack of cerium and neodymium. Andradite itself is rare in pegmatites. Possible mechanisms of ionic substitution are Y (super 3+) +(Fe (super 3+) , Al (super 3+) ) Ca (super 2+) +Si (super 4+) and Mn (super 2+) Ca (super 2+) .