I have tried it on white paper, a dark background, and a number of people tried to take a picture of it today on various backgrounds with various cameras, to no avail. There is too much detail to pick up in the murrini, some of it definite and some of it shiny silver glass. Not sure what to do with it now ...

I think what I'd try next is to do one on a little cab or lentil that wasn't white. Or it might actually be much easier to see if it was part of a big fancy bead that also had shimmery colours in it. (I'm kinda thinking of Anouk's focals - they often have fancy silver glass murrini, but they show up well against the rest of it).
It's a lovely murrini, we can see that much! If it's to sell some, that pic along with a photo of the slices gives a good enough idea if it just won't cooperate, I think.