ruby studded medal: stonegrabbers in dawnshroud to the left and out slightly from the zone to neth.
jewel: random drop from one of the zones... dawnshroud probably. don't remember exactly which.
mark: actually got this from my partner who got it while hunting in tene mnts. grol baku chanter
fancy necklace: still working on this. been kiting the shadows in twilight sea (island near teleporter to fungus grove) but have only seen one named that is for twilight armor, and it wasn't the tenacious, which is what drops the necklace.
i'm just getting this because it's purple and would go well with my full suit of blue. :)