I bought these 5 strands from Drammeh Brothers in 1996. Fairly expensive then, the equivalent of about $150 each strand now.
The "Russian" cut beads are from 6-sided cane, the cut ovals from octagonal cane, with 40 facets, and feel as if the glass might have some lead in it. The ovals are different sizes and have no tint of brown in them, which make me think they're similar to the inky blue 50-facet versions on the "Traded for Slaves" cards - i.e., they were hand cut, not molded and ground. Although the beads appear to be in pristine, un-worn condition, I do think they're pre-World War 1 - hexagonal purple canes can be seen in the plates of W. Neuwirth's book Perlen Aus Gabblonz, with a bunch of cut beads dated to 1837.
So I took apart 3 strands and re-strung them as shown. A nice, comfortable necklace with no clasp to fool with or to come unfastened at unexpected moments. I rather like the way the cut beads more resemble amethyst chunks than molded crystal beads.
Nonetheless, the thought of selling this necklace at $450 - less than materials cost, not counting design time - strikes me as laughable. So will content myself with swanking around in something unique that nobody else has, even it it does resemble ordinary costume jewelry.
[If you have 50 strands of these purple "Russians," don't tell me.]