Black Mamba Boulder is an odd, black boulder studded with quartz and lumps of iron under the power lines. It is highly featured and much smoother than the typical granite in the area making it an excellent warm-up boulder. Be watchful for loose rock. I pulled off a few large chunks when feeling out routes that I thought were solid.
The rock seeps a bit after rains suggesting that it is riddled with cracks and probably won't hold up well to freeze thaw cycles and will likely shed quite a bit every spring.