Your spoiler suggests that perhaps a bonus to Search and Appraise is appropriate, or perhaps spells that allow one to find things and identify them, or perhaps look for traps as a rogue (ie: 'Find Traps'). The rose, however, suggests something regarding safety - which could be anything from Endurance to 'Cure Lesser Wounds' to 'Endure Elements' to 'Protection from Evil' to 'Shield of Faith' or 'Sanctuary'. Even 'Consecrate' or 'Lesser Restoration' might work, or perhaps a combination of the two or three of these.
She is likely praying for his safe return, so perhaps 'Consecrate' is in action while the rose lives, and so long as the amulet is worn the wearer has the benefit of the feat Endurance and the spell 'Endure Elements.' Furthermore, once per day the wearer may call upon one of the following effects: 'Cure Lesser Wounds,' 'Shield of Faith,' 'Sanctuary,' or the Diehard feat.
If you wish to make it more potent - or if you wish to focus more on the 'finding useful items' - then perhaps you could have it grant the wearer both Trapfinding (as a Rogue) and a +4 bonus to Appraise, Disable Device, and Search skills, and a +2 bonus to Knowledge skills in general (Geography, History, Religion, etc). These would make it easier to identify useful items, to find them, and to evade any traps associated with them - and all are typically cross-class skills to Warriors and Fighters. Furthermore, once per day the wearer can cast one of the following: 'Find Traps,' 'Identify,' 'Locate Object,' or 'Remove Curse.'
Combining the two groups of effects into one objects might be a bit powerful, but from what you've said earlier it sounds like you use fewer magic items with more power rather than a plethora of magic items with scattered powers. In any case, both together work out to an amulet that grants Endurance, 'Endure Elements,' a few skill bonuses (+4 to Appraise, Disable Device, Search, +2 to some Knowledge skills), and Trapfinding. Furthermore, twice per day the wearer can cast a spell - once only from each of two lists. Or they can utilize 'Die Hard' once in exchange for casting a spell from the first list.
All in all it may not be quite as powerful as at first seems. The most potent aspect, arguably, is the Knowledge bonus, but I can see that being reduced to allowing a Knowledge check even if no ranks are in the skill, and granting a +2 bonus to specific knowledges (Geography, History, Local [hometown], and Religion perhaps being most useful.