together with aragonite and conchiolin, this crystalline form of natural calcium carbonate make up the structure of nacre.

calcium carbonate

 what pearls are mainly composed of


a process on examining a pearl in front of a focused light source to check if it shows the layered structure that proves it contains a bead nucleus


a weight measure used for natural pearls


 a reddish overtone found on pearls produced by Pinctada margaritifera

choker necklace

 a necklace that lie above the collar bone, and is 14 to 16 inches in length


 The Confédération Internationale de la Bijouterie, Joaillerie et Orfèvrerie is also known as the World Jewellery Confederation, an international confederation of jewelry, gemstone, horology, and silverware trade organizations

circled pearls

 pearls with raised concentric rings around its surface

clam pearls

 non-nacreous pearls found in clams

coin pearls

 coin-shaped bead-and-tissue-cultured pearls

collar necklace

a necklace measuring 10 to 13 inches (25 to 33 cm)

concentric structure

the layering of calcium carbonate crystals that is characteristic of natural pearls, tissue-cultured pearls, bead-cultured pearls, and the nacre layer of bead-and-tissue-cultured pearls

conch pearls

 non-nacreous pearls formed by the conch shell


the organic element that acts like glue and binds crystals together

Cortez pearls

 trade name for Pteria sterna in the Gulf of California, which is also called the Sea of Cortez

cultured pearls

pearls produced by the human insertion of a bead in a freshwater mussel or saltwater mollusk