Personally, I think it's impossible to be certain without looking at them with a loupe. Even fifteen years ago there were a lot of very competent replicas being made, and now they have gotten much better - or worse, depending on one's point of view. I'm inclined to think that two of these - red/white/blue and blue/white red canes - are likely to be copies and I would steer away from them, while the third with the green base might be more authentic. But if they all came from the same seller, why would two be fake and one real? (I've seen almost no authentic Jatims in Chatuchak in the past fifteen years or so; there were some before that.)

My doubts come first of all from the absence of wear on the two I mentioned. It's possible, though, that they've been refinished - polished/ground - but I can't see any signs of that in the photos. A fairly large proportion of the beads that were dug up ten to twenty years ago were polished by dealers, and iIf you do see polish marks on the surface, ironically that's a fairly good indicator that they're "authentic." But it's the areas around the perforations that make me most suspicious; they're too finished, and the finish is at odds with the method of manufacture. The best source for pictures is Jamey Allen's book "Magical Ancient Beads," and if you look at those illustrations, I think you'll see what I mean.

I'll attach a couple more images of beads that I'm sure of that also look substantially different.

Incidentally, as I said in a recent thread about Byzantine beads, the name Majapahit is a misnomer for these beads. The original Jatims were made in the 5th or 6th centuries or thereabouts, and the Majapahit period was 800-1,000 years later. There's no sign of Jatims in any Majapahit site that I've heard of; the beads that were worn then and that appear in excavations were gold or stone, or heirloomed Indo-Pacific glass beads.

All the best,

Will