A rock crusher is attached to a typical excavator that has a swing boom, an extension arm attached to the swing boom, and a bucket attached to the extension arm. The rock crusher has at least one blade fixedly attached within the bucket's interior and at least one anvil fixedly attached to the extension arm just above the bucket. At least one other blade is pivotally attached to the extension arm as well as to the swing boom via a linkage so that when the extension arm is drawn toward the boom by pulling back on the operator's stick, this second blade is crushingly pressed onto the material within the bucket.