Two axes are the same length and lie on a horizontal plane. The third axis is not the same length and is at a right angle to the other two. Each crystal has four axes of symmetry. The fourth axis is not the same length, and is perpendicular to other three. Each crystal has three unequal axes, all at right angles to one another.
Crystals are short and stubby with tilted faces at each end.
Each crystal has three unequal axes. Two axes lie in the same plane at right angles to each other. The third axis is inclined. Each crystal has three unequal axes. None are perpendicular to one another.