Calc-alkaline dikes have diamonds
If you do a google search for Wawa diamonds alkaline dikes you'll find a few references of what they'd be looking for. Some reports of fairly technical, but here's one that discusses diamonds in calc-alkaline lamprophyre dikes: https://connection.ebscohost.com/c/articles/19996044/enigmatic-diamonds-archean-calc-alkaline-lamprophyres-wawa-southern-ontario-canada