Hello! I am in the middle a research Project studying Prismatic Lead White, a type of lead white that presumably appeared during the 1850s. In dispersion and observed with Polarised Light Microscopy, it produced characteristic little prisms. It was apparently a pigment used by Turner. Lead white has been used since the Antiquity and we tend to overlook it in painted works, but this particular one appeared later and can help us date paintings as well as detect forgeries. See: http://www.npg.org.uk/research/programmes/making-art-in-tudor-britain/case-studies/matb-case-study-5.php At the moment, I am having difficulty researching on it as I do not know the name under which it was sold at the time. Definitely not Prismatic Lead White! Getting a name for it would help me search for the manufacture process and understand in what aspect(s) it is different from lead white. If you have the slightest idea, I would be happy to hear it. Cheers :)
I'm not sure your timeline is terribly accurate Turner died in 1851, for one thing. There does appear to have been a change in the manufacturing process of these pigments ca. 1850 that resulted in less content of other metals, especially silver, copper, mercury, manganese, and chromium.
Here's a very old source on the subject:
Gettens, Rutherford J., Hermann Kühn, and W. T. Chase. 1967. “Lead White”. Studies in Conservation 12 (4). [Maney Publishing, International Institute for Conservation of Historic and Artistic Works]: 125–39.
From perusing the conservation journals, it appears that there might be differences in trace element contents as well as the specific lead compound used that might account for the prismatic nature of these specific pigments. But I have to admit, conservators use a lot of chemistry, a subject I haven't studied since high school.
If all else fails, you may contact Harvard's Ford Pigment Library, whose curators may have some further follow-ups.