Form and Definition
This criterion assesses crystal sharpness, termination, and form. For this judgment, crystal faces should form without interruption. Angles and planes should intersect with clean definable lines. Also, consider the sharpness of the crystal edges, which is dependent upon the species. Ask if the terminations are symmetrical, proportionate, well defined, and attractively shaped. The sides and faces of each crystal should be well developed. Terminations that are complex are usually more desirable. They should attract your eye and not distract.