Symmetry
How evenly a pearl or stone is balanced around its own axis. What separates a fine drop from a baroque one.
For pearls, symmetry decides which grade a shape lands in. A drop that is even on both sides of its axis is a premium shape; the same pearl leaning to one side is baroque.
For cut stones it is a formal grading factor covering facet alignment, outline evenness and how well the two halves mirror each other.
It is judged by eye at arm's length, and it shows up far more in wear than on paper.
When you are buying
Look at a drop or pear in profile as well as face on. Most asymmetry hides from the front and is obvious from the side.
Drop
Tapered at one end and rounded at the other, like a teardrop. Highly valued when the taper is symmetrical.
Pear
A drop with a more pronounced shoulder, wider at the base and distinctly narrow at the top.
Baroque
Any pearl with no axis of symmetry. Once treated as a reject, now the shape most associated with contemporary pearl design.
Cut
How a stone is shaped and faceted. The one thing that most affects how it looks, and the one buyers examine least.
Matching
How consistently the pearls within one piece agree on size, colour, lustre and shape. A grading factor in its own right.