A few years ago now, after having passed on acquiring "sea sediment jasper" beads I have: 1) bought a few of these; and 2) participated at some mineralogical fora, where this topic was pursued.

I have come to the inevitable conclusion that "sea sediment jasper" is a totally artificial material (!).

It is apparently a reconstructed material, possibly made from pulverized agate (or some convenient stone dust), glued-together (with epoxy or something else), and artificially hardened, so that it more-strongly resembles a hard stone. Also, the material is routinely presented in a variety of colors (some being very unnatural—like bright pink)—and some effort has been extended to make the material resemble the appearance of brecciated jasper.

So, this stuff is just a cheap fake. Jamey