This lucky shot proved impossible to reproduce, and not for lack of trying! The white vortex floating over an iridescent field, is part of the same aragonite scroll forming a phenomenal white flame pearl. It so happens that the tight core of the aragonite scroll scatters light—hence the appropriate translucent cloud-white, lower scroll sheets flare away just right for rainbow diffraction, and the mass of aragonite in between is transparent enough to all but disappear from view; you’d think of the play of light through classical 'phenomenals' in such terms—such flame patterns are one digression away. Back in the day when I had first seen such pearls, their owner, Stephen Metzler, would compare the white flame patterns with great storms (so does NASA)—naming such pearls 'badai' (storm, Malay). His best earned a title of perfection—'badai sempuna' (perfect storm).
Today, six 'storms' sit on my desk—among a handful of samples awaiting the new year.
Much to be said of each of these pearls, and there are plenty more. Gathering a reasonable collection of samples seems to have impressed the notion that natural pearls are a neatly distinct case of (biogenic) mineralization, worthy of academic curiosity. Such enterprises do not, customarily, end. I have certainly underestimated how large the subject might get, expanding rather far away from the concerns of pearl gemmology, or from that early fascination with wild beauty and its perfect storms... I'd say, next year let badai be back: beyond all else, these pearls stand out for their unique crystallography among related shell materials freshly reviewed.*
The other pearls lead to two lines of investigation: hunting for the beginning of natural pearl forming (Mytilus) and, should the large matter prove containable—giving a precise treatment to one of the historically famous details of natural pearls—their relatively prominent layers. Neither is a small subject, neither particularly straightforward to blog. Yet, some of the work requires fresh pearl collecting—something I had wished to dwell on for a while. There will be news, and they will gather here.
* Almagro, Io, et al. "New crystallographic relationships in biogenic aragonite: the crossed-lamellar microstructures of mollusks." Crystal Growth & Design 16.4 (2016): 2083–2093.