Hi Richard,

They are simply translations of German terms that I picked up from other collectors. The German terms are "wildes Wasser" for the diffraction glow of pearls with large surfaces like baroques that have the flirring iridescence of butterfly wings (that is also the type of iridescence seen on coin pearls and flat mother of pearl) and "stilles Wasser" (transformed in English into deep water since the German saying goes "stille Wasser sind tief" or quiet waters are deep, for the refractive iridescence of very clear nacre with the light passing through various translucent layers of aragonite where the platelets face in different directions). Freshadamas have deep water, abalones have wild water, and the pterias from the teaching strand you saw have both at the same time.

Zeide