I love the idea of black glass in contrast with natural or warm spaces, like wood or warm stone. There's a contrast in temperature, as well as quality of material. To me, wood is organic and connected to emotion while black glass is sleek and impartial.
At the Dollar Tree, purchase one glass candle holder or vase and one pouch of stones. I chose natural, but you can also choose glass beads to match the color of your bathroom! Simply place the stones into the vase and add toothbrushes!