Pearls of Australia employs a comprehensive grading system based on our seven virtues: Colour, Lustre, Shape, Size, Surface, Provenance and Purity.
What makes a pearl highly valuable is the rarity of its characteristic or virtues, therefore the more spherical a pearl's shape is, the higher the lustre, the larger the size, and the better the surface quality.
Surface quality is assed by the presence of blemishes or imperfections on the pearl's surface.
Nacre quality refers to the thickness and quality of the nacre; the substance secreted by the pearl shell that forms the pearl.
Matching refers to the uniformity of the pearls in a strand or pair of earrings. Well-matched pearls consider the size, shape, colour, lustre and surface quality.