Freashwater Pearls made from fresh water sources, often from manmade sources.  These pearls are from organic sources and vary in size, shape, and color.
Grade A pearls contain less than 10% imperfections to the surface and are almost entirely smooth with very few ripples or indentations.  The luster is extremely good.  Most pearls will fall into the B grade.
Grade B pearls contain some imperfections over less than 30% of the surface and can still have a beautiful luster to them.
Grade C pearls contain some ripples and imperfections over less than 70% of their surface and have an average luster.
Grade D pearls contain imperfections over more than 70% of their surface but not extreme.  This is the lowest grade a pearl can be.