This teardrop aromatherapy locket diffuser by Cornucopia Brands is gorgeous and perfect for essential oils anywhere you go, right around your neck.
It comes with 4 puff balls in 4 different colors, to put essential oils on, and then enclose them on the locket. You then weave the chain back through; this keeps the locket in place so it doesn't open up accidentally.
It is very inexpensive -- only $14.99! And the chain is good quality as well. It comes with the teardrop locket pendant, the chain I mentioned, 4 diffuser balls for the inside of the locket pendant, and it also comes with some pipettes to help you put the essential oil on the balls, but I don't think those are necessary. :)
The puff balls (diffuser balls) can be soaked with whatever scent you want (lemongrass, anyone??) all you have to do is pour some drops of your favorite essential oils onto it. It is very absorbent and the scent lasts a long while.