Freshwater pearls or saltwater pearls?

Here is a simple question. How many freshwater pearls are there in this image ?

Pearls have fascinated us for hundreds of years with their colours, shapes and diversity. Despite our long love story with pearls, our general knowledge of these pretty and precious gems is still relatively poor. A simple test of our understanding is whether we can explain the difference between a freshwater and a saltwater pearl…

Saltwater pearls include Akoya pearls historically from Japan, Tahitian pearls from French Polynesia and South Sea pearls from Australia and Indonesia, whilst Freshwater pearls today originate mainly from China. The difference between saltwater and freshwater pearls is not their geographic origin, however, but in the mollusks in which they originate.

Saltwater pearls are found in oysters that live in saltwater oceans and seas, whilst freshwater pearls are found in mussels that live in freshwater rivers, lakes and ponds.

Both saltwater and freshwater pearls are formed with a similar process. All pearls are formed as the mollusk secretes layers of a protective iridescent substance called nacre around an irritant. In natural pearls an irritant such as a parasite enters the mollusk, whereas with cultured pearls, this irritant is introduced intentionally by man. Experts define both saltwater and freshwater pearls as ‘pearls’ for they have concentric layers of nacre.

Both freshwater and saltwater pearls make beautiful jewellery. Their unique characteristics of each variety make it not too difficult to distinguish a freshwater pearl from a saltwater pearl by looking at its natural colour, its shape, its size and whether the pearl has a bead nucleus inside. Metallic pastel colours, for example, are a clear sign that a pearl is of freshwater origin. A knowledgeable eye might look at the drill hole of the pearl to determine if there is a shell bead nucleus inside.

Continual advances in pearl farming techniques, for example with the introduction of round beaded nuclei to help make larger round freshwater pearls, are making some of these differences harder to identify. With some significant differences in price between freshwater and saltwater pearls, it is always advisable to purchase pearls from a reputable jeweller.

PS The answer above is that there are 5 cultured freshwater pearls in the image above, the rest are all cultured saltwater pearls.