The Geas negative quality in Street Magic, can Adepts take it? It's just that the description makes it seem like it's meant more for spellslingers.

Reason is I've been planning out a gunslinging adept and thought it might be interesting to have him start a game with a talisman geas, not due to his magic failing him, but that it was always kind of unstable (mechanically, it'd be the same as a broken geas, just that that's how his powers are normally).

I assume a silver medallion with a pair of inset rubies would do for an (albeit expensive) talisman?

Yes, any Awakened character can take Geasa as a Negative Quality during Chargen. In the description to the Quality it actually speaks to how it works for Adepts (minus 1 PP)

Note: I should be clear that the Negative Quality is different from the "Tweaking the Rules" geasa and adepts.

Well, the text refers to "Awakened", so yes, I believe Adepts qualify.
And yes, judging by the fact that rings are used as an example of fetishes, and the rules for creating talismans and fetishes are the same and in the same paragraph, I'd say that yes, a silver medallion with a pair of inset rubies would do for a talisman.

Thanks, I thought it was for adepts but wasn't sure. And I guess I skimmed over that loss of a power point bit. Small pain but I think I can work around it.

I was asking about the talisman composition since the Geas quality's description mentions that it needs three distinct characteristics describing it. Would the third have to be another material used in making it (say a precious metal for the chain?) or could it just be having the medallion shaped like an animal head?

Frankly, you're better off asking your GM here.

Ahk, thanks. Well it'll be shaped like a wolf's head anyway, and if the shape doesn't count then I'll just do something with the chain. The example talisman in the quality's description gets away with a gold chain for the third characteristic.

And even though I'm planning to take the Albino negative quality as well, he's not going to be an expy of Geralt of Rivia (probably won't be able to wield a sword to save his life, for one and his snarkiness'll be less "angered anti-hero" and more "Cyberpunk Blackadder"). I will make him a fan of the books, though, just for the hell of it and to explain where the idea for his talisman's design came from.