Stealing? Lost?

I have recently (in the last two months) looked for several pieces of jewelry that I have had since I moved here (as in, have worn since then) and have discovered that they are not in my armoire, not in my boxes, not in my steampunk acquisitions… They are nowhere in the house.

1. mystic topaz ring (5-stone) sterling silver
2. natural blue topaz earrings in white gold R purchased for me from Jarred’s Fine Jewelers
3. natural blue topaz necklace that matches it that he bought at same place
4. small (fits my pinkie) pink star sapphire ring that was my grandmother’s (and possibly my great-grandmother’s, as she was very tiny)
5. my Victorian pin to which I had affixed copper charms of jewelry (about an inch long each, five of them). The original pin was probably 4×2.5 (inches)
6. my grandmother’s silver ring with three small circular stones (amethyst, peridot, and aquamarine).

I know that “gremlins” get in our house and walk off with odd things, but who or what is walking off with my jewelry?

Update: I found the Victorian pin with copper charms in a box with a pair of shoes I wear with it. I’ve looked through the other boxes and haven’t found anything else yet. Maybe I will, though.