Freshwater Pearl Quality Guide

Pearls are unique among gemstones in that they are natural, organic products of living creatures. So Whether seawater pearls or freshwater pearls, judging their quality, mainly from the following four aspects:

  • SHAPE: Generally speaking, pearls should be round, and the rounder the better.
  • LUSTRE: Lustre is the soul of pearls, the stronger the lustre, the better the quality. The pearl itself does not emit light. The lustre of the pearl is the reflected light. The smoother and more delicate the pearl skin, the stronger the reflected light.
  • SURFACE: that is, the degree of blemishes. The fewer blemishes, the higher the finish, and the better the quality.
  • SIZE: If a high quality pearl is larger than usual for its type, it will be worth more than smaller pearls o jewelleryf the same type. 

Therefore, it is necessary to measure whether the shape, size, quality, colour, etc. of these pearls match. The higher the matching degree, the better.



There are five primary pearl shapes: round, semi-round, drop, baroque, and circle baroque. We describe each shape with more detail below.

pearl shape

In general, round and near-round pearls are the most valuable due to their rarity. Symmetrical shapes are generally considered to be more desirable than baroque shapes. Baroques, however, can be extremely unique thus increasing their desirability more than might be expected based on their shape alone. A perfectly round pearl is very rare. The rounder the pearl, the more valuable it is. 


Lustre is the most important of all the value factors.

Lustre is more than a combination of surface brilliance and a deep glow. It is caused by light travelling down through the translucent layers of nacre and reflecting back to the eye from deep within the pearl.

pearl lustreThere are four categories of lustre:

  • Excellent - reflections are bright, sharp and distinct.
  • Good - reflections are bright but not sharp and they are slightly hazy around the edges.
  • Fair - reflections are weak, hazy and/or blurred.
  • Poor - reflections are dim and diffused.

The highest quality pearls have a sharp, mirror-like lustre showing a high level of reflection.


Starry Night 18K Gold Freshwater Pearl Necklace
Our Excellent  lustre pearl necklace
Our Excellent lustre pearl necklace(9-10 mm)


Pearls are organic so it is not surprising that they show surface qualities. The cleaner the surface of the pearl, the more valuable it is. The surface of the pearl will be more or less with some growth lines, pits and other defects, there is no 100% flawless pearl, even if the surface of the pearl is flawless, if you look at it with a magnifying glass, you will find that the surface of the pearl has a dune-like feature. 

There are four classifications:

pearl surface

  • Clean - pearls can be blemish free or contain minute surface characteristics that are very difficult to see.
  • Lightly Blemished - minor blemishes or surface irregularities.
  • Moderately Blemished - noticeable surface characteristics.
  • Heavily Blemished - obvious surface irregularities.


Freshwater pearls are generally between 3-12 mm in diameter.

Pearls are measured by their diameter in millimetres. If all other quality factors are equal, the size of a pearl will determine its value. Only a 1 millimetre increase in pearl size will be a substantial jump in both appearance and value. The importance of a pearl's size to its ultimate value depends on the pearl type. If a high quality pearl is larger than usual for its type, it will be worth more than smaller pearls of the same type. 

pearl size