There are lots of snake-safe options. You need to get the animal off the pine shavings in any case; the aromatic compounds in pine are bad news for herps (mammals too). Pay no attention to what the packing says.
Smooth, pea-gravel type aquarium rock isn't exactly an inherently unsafe option, though it may get too hot for safety. It will, however, be a bit problematic for cleaning. It will also prevent your snake from burrowing, which a lot of snakes really enjoy and which helps them to feel safe.
There's nothing wrong with choosing a substrate to color coordinate with your pet, just make it a safe one! Darker-colored choices that are snake-friendly include Repti-bark, coconut husk, and cypress mulch. Of the three, the cypress mulch may be easiest to find since virtually every garden center carries it.