Noting the system of crystallization which has three unequal axes at right angles to each other; trimetric. See Crystallization.

A crystal system where the cell sizes (a,b,c) have different lengths, but all of the inter-axis angles are 90deg. This has no tetrads (axes of 4-fold rotational symmetry) or triads (axes of 3-fold symmetry). It does have 3 diads (axes of 2-fold symmetry), centred in the middle of each face.

These crystals are short and stubby. Each crystal has three unequal axes, all at right angles to one another. Example: topaz

NEED A DEFINITION.