Pseudolimea cf. acuticosta (Goldfuss)

Ludwigia - Why is it that so many of your aragonitic shells have such a traslucent look? Have they been altered to calcite, or silica?

Most of the originally aragonitic shells in this gallery have long since been altered to calcite, but I apply a coat of a beeswax finish called Rember to most of my fossils, so that's probably what you're seeing.