Freshwater AK pearl, known as “film seed pearl” in industry, is the latest nucleated cultured pearl research. Freshwater AK pearls are characterized by good roundness and a high proportion of perfect roundness, small diameter, mainly 5-9mm same as Akoya pearl. The luster of the freshwater AK pearl is better than that of conventional Freshwater pearl and can be comparable to Japanese Akoya pearl. And Freshwater AK pearl with about over 2mm nacre is much thicker than Akoya pearl which is 0.6mm, the surface clean is better than Akoya pearl.
Here is a video of some freshwater AK pearl details.
So if you like small pearls, Freshwater AK pearl will be your good choice except for Akoya.