In the Idaho Panhandle there are innumerable exposures of dissimilar rocks in glaring juxtaposition. Geologists tell us this was once North America's western beachfront. But multiple errant land masses, carried by plate tectonics, crashed into Idaho, and then more pressed against them, filling in the entire states of Oregon and Washington.
Near the town of Blanchard, a vein of this tan and black rock stands out on a hillside, right next to what I call the Blanchard Red. While I'm fascinated by polarized light microscopy, I have not yet had the geologic training to say with certainty what these crystals are. It may be a pegmatite dike, but the red is not on both sides. Still, they too dance gracefully to polarized light!
Thin sections of Blanchard White have large, easily viewed birefringent crystals, allowing the brighter, ~15X lens to show them to best advantage.