There are quite a few past posts here, that discuss these glass beads from India.
They first appeared in the American marketplace, as new products in 1974. I still have the ones I bought then.
By the late 1980s or early 1990s, these were routinely misrepresented as "old Naga beads"—which was total nonsense.
There are been a number of editions, or slight changes over forty-eight years, including other sizes and shapes, some of which have resulted from press-molding. Some have been matted, though many remain shiny. But, essentially, these are all furnace-would glass beads composed from marbleized glass globs, that take on the spiraling structure, due to the winding method.
These are some late versions of said beads.
This is a photo-rich discussion: