Paragon: this term was formerly used to designate large and exceptionally perfect or beautiful pearls, usually weighing over one hundred grains.
Round: when the pearl is absolutely spherical, as if turned on a lathe, without any flattening or any indentations on the sides.
Button or Bouton: if the pearl is domed on top and has either a flat or slightly convex back.
Pear-shaped: when the pearl is formed like a pear, terminating in a point, and is either flat at the lower end or rounded.
Drop-shaped: when the pearl is elongated like a pear, but is larger at the lower end than a pear-shaped pearl.
Egg-shaped: when ovate in form, rounded more or less at each end, or formed like an egg.
Cone-shaped: applied to pearls that are elongated and rounded with one flat end, and have the form of a cone.
Top-shaped: a name given to those pearls that are broad, flattened at the top and rounded on the sides, terminating in a point, like a top.
Seed-pearls is a name given to pearls that are round or irregular, and weigh one fourth grain or even less. They are frequently so small that 18,000 are contained in a single ounce, and they are often sent from the East in bunches of about a dozen or so of strings.
Dust-pearls. When seed-pearls are very small they are known as “dust-pearls”; they are really as fine as dust and have very little value; still, their form is in many cases wonderfully perfect.