The host rock looks like some pics I've seen of kimberlite. The surface was rough and angular, so I don't think it traveled far. I could be wrong. I do know that there is a lamprophyre about 30 miles northeast of me. Whether or not this is a piece of it, I really don't know, but it's entirely possible that glaciers could have deposited it.
Along with diamonds found in that lamprophyre, there were also zircon, spinel and purple, red and orange pyrope garnets. The spinel and zircon are described as "Various spinels are present in the heavy mineral concentrates. Some are reasonably Cr-rich, with up to 58 wl% Cr203 plus appreciable MgO and A12O3. Other spinels include magnetite and titanomagnetite. Coarse honey-yellow to orange-brown zircon crystals are quite common.These grains are typically anhedral, rarely subhedral, and are mantled by fine-grained reaction products, possibly baddeleyite." To my knowledge there haven't been any sapphires found here.
I'm thinking maybe spinel or diamond. I've taken these to a couple gemologists, one couldn't or wouldn't even say what she thought they were, and the other was leaning toward zircon. I'm going to pick up a cheap microscope attachment for my phone and will see if I can get some better pics.