We wouldn’t think of putting fresh, delicious preserves and throwing stars together in a blender, but that’s essentially what the Japanese jewelry label Jam Home Made does with each new collection. For each season the designers balance weighty-looking materials with unexpected  — and sometimes sweet — looks. For instance, in one collection they created a “college ring” that replaced the spaces usually reserved for letters with binary code, and in another there’s a lock and key necklace that come as a pair, one unlocking the other. Excellent conversation pieces.