Have you tried using shell pearls? They are fabulous--so nice in fact that I ooked high & low to find a reasonably-priced source for them. Once you try them you will be hooked too!
A cross between real and faux gemstone, the shell pearl has become popular for its perfect shape, feel and cost. Shell pearls are a genuine shell bead (usually mother of pearl) with a pearlized coating. The core is made from the same type of shells that produce real pearls. Therefore, the center of a shell pearl is its most important trait, bestowing weight, value and durability.
Shell pearls closely imitate the precise roundness and shine of oriental pearls, at a fraction of the cost. Their shell center also gives them a similar weight and feel to their expensive counterparts. In fact, the imitation is so fine that if you laid shell pearls next to cultured South Sea pearls of comparable quality and color, you wouldn't be able distinguish them. No matter how close the imitation, however, a shell pearl can easily be detected by the tooth test and by looking closely around the hole the shell color inside is visible, and the pearly finish is often chipped just around the hole. But these issues are unnoticeable once the bead is strung.
The finish on shell pearls will sometimes exhibit pock marks and nicks, like a freshwater pearl. Shell pearls are easier to care for than natural pearls; they are much less affected by sweat, perfume and detergents, and have a more durable shine and color.