Freshwater pearls and Akoya pearls differ in the type of luster, first of all. In appearance Freshwater pearls are noted for a softer luster, a glow that comes from deep within the pearl. Akoya pearls have a more brilliant, almost mirror like luster.
The difference is due to the type of mollusc that produces the pearls and the difference in thickness of the nacre. Freshwater pearls have thicker nacre as seen in the explanation to the right.
Freshwater pearls are less expensive. They are grown in lakes, ponds and rivers. A freshwater mollusk can create up to 50 pearls at a time, as opposed to an Akoya pearl oyster that will produce only one to three pearls at a time. This accounts for the difference in price. The process to grow a freshwater pearl takes between 4 to 6 years and is full of peril - risk of disease, pollution, etc. However Akoya pearls risk additional perils in the sea.
Freshwater pearls have thicker nacre than saltwater pearls. Since the pearls in the freshwater mollusk start from virtually nothing (a small piece of tissue from a freshwater oyster), they are essentially 100% nacre. So for a pearl that is 7.5mm, the nacre will be 7.5mm in diameter! The freshwater pearl growth process is almost identical to the growth of 'natural' pearls. This makes for more durable pearl necklaces, as a thin layer of nacre can more easily chip, peel or be worn down through wear. This might be a consideration if you're thinking not just of wearing the pearls yourself for the next few years, but handing them down to the next generation.
With modern freshwater cultivation methods, freshwater pearl necklaces are of increasingly good quality - with excellent body, shape, and luster and can be on equal footing with that of Saltwater Akoya pearls. In fact, in some cases the harvest of Freshwater cultured pearls has brought about pearls of such incredible quality and luster that they have been compared to the finest Akoya Pearls. The Freshwater Orient pearls are one example of these superior quality freshwater pearl necklaces.
The term "Akoya" is mostly used internationally to signify Saltwater Pearls from Japan. And so, Akoya pearls have been adopted in the industry to stand for saltwater pearls made in Japan. Akoya Saltwater Pearls are grown and cultivated in the ocean along the coast of Japan and China. The Akoya mollusk (Pinctada fucata) is implanted with a round bead along with a small piece of mantle tissue and nacre envelops around the bead. The bead implants are made from oyster shells and are usually slightly smaller than the final pearl product. The number of beads that can be inserted into the mollusk depends on the mollusk, but usually not more than 3 beads can be inserted into one mollusk.
The growing time for Saltwater Akoya Pearls take between 6 to 18 months - the slower the growing period the better as the nacre is smoother and even - but the longer the pearl is grown in the ocean the higher risk of damage, storms, mollusk dying, etc - so the price for Akoya pearls will fluctuate enormously with the thickness of nacre and the risk taken.
In the recent years Akoya pearls and their status as the pearl necklaces of choice has been significantly challenged by the outstanding quality of Freshwater pearl necklaces, especially notable being the exceptionally high luster freshwater orient collection. This new generation of freshwater pearls rival in quality the Akoya pearls at a fraction of the Akoya price. When freshwater pearls are round, they are magnificent - the nacre is full, the molecular structure of the nacre is tightly bound and the lustre can be excellent.
However, Akoya pearls still have the prestige of being the traditional high quality pearls. AAA Akoya pearls are perfectly round and have that characteristic luster we have come to expect of the finest pearls. The finest of the AAA Akoya pearls have a special category of their own. They are known as Hanadama pearls and are truly spectacular. Breathtakingly beautiful, a necklace made from these pearls is a treasure.
What's the difference between cultured and natural Pearls?
What are Mikimoto Pearls?
See examples of beautiful Akoya Pearls
See for yourself stunning examples of Freshwater Pearls