adjective: (mineralogy) Of or pertaining to a wedge-shaped crystal form of the tetragonal or orthorhombic system.
adjective: (mineralogy) Of or pertaining to a crystal form bounded by eight scalene triangles arranged in pairs, constituting a tetragonal scalenohedron.
noun: (geometry) A non-regular tetrahedron whose four faces are congruent acute-angled triangles.
