Pearl classification

Pearls have always exerted a particular charm that has fed legends and myths. In Greek pearls are distinguished by the name “margarites” and in Latin, “perula” (small bag), “pilula” (small sphere) and finally “perla”.

The oldest pearl jewellery piece in the world is a three-string pearl necklace (composed of 216 pearls) found in an Egyptian sarcophagus. In ancient times pearls were widely used in Greece and Rome, right up until the most recent Renaissance. The largest known pearl was found in Taiwan and has a weight of 7 Kg, it was produced by a giant clam (Tridacna gigas).

Pearls are concretions produced by certain species of marine or freshwater molluscs, without any intervention from man (natural pearls) or with intervention from man (cultured pearls with or withoutnucleus).

Pearls are made up for the most part by calcium carbonate (CaCO3), generally in the form of aragonite, and to a lesser extent by organic matter (conchiolin 4-14 %) and water for the remainder 2-4 %.

Classificazione delle perle

  • Natural pearls
    • salt water
    • fresh water
  • Cultured pearls
    • salt water
      • with bead
      • without bead
    • fresh water
      • with bead
      • without bead
  • Assembled/Composite blister
  • Imitation pearls

Salt water pearl molluscs

The main salt water mollusc producers of pearls are bivalve of the Pinctada genus (commonly called “oysters”), they can be found in the Persian Gulf, Red Sea, Polynesia, Pacific coast of Central America, seas of Japan and China, the coasts of Venezuela and Sri Lanka, Indonesia, the Australian coasts and Mexico.

Amongst the salt water bivalve mollusc genera/species there are the Pteria (eastern Pacific, Gulf of California, Indo-Pacific area), Tridacna (Indo-Pacific Ocean), Mercenaria Mercenaria (Atlantic Ocean) and Pinna Nobilis (Mediterranean Sea, Red Sea).
Finally, there are several gastropods such as the Haliotis (the basis for the name of our brand), the Strombus Gigas, the Melo Melo, the Trochus, the Turbo and the Pecten.

From salt water come the famous AKOYA white pearls (cultured pearls with nucleus, obtained from the Pinctada Fucata or Martensii), the “South Sea” pearls (obtained from culturing of the Pinctada Maxima) and Tahitian pearls (obtained from culturing of the Pinctada Margaritifera).

 

Freshwater pearl molluscs

Freshwater pearl molluscs belong to the large family of Unionidi, widespread in the freshwaters of Asia, Europe and North America and they produce white or coloured pearls, which may have irregular or perfectly spherical shape.