How common is boron?
Not very. Boron makes up about one thousandth of a percent of Earth's crust.
Several allotropes of boron exist: amorphous boron is a brown powder; whereas crystalline boron is black, extremely hard (about 9.5 on Mohs' scale), and a poor conductor at room temperature. Elemental boron is used as a dopant in the semiconductor industry, while boron compounds play important roles as light structural materials, insecticides and preservatives, and reagents for chemical synthesis. basically...yes.