Erica Weiner is quite the eco-enthusiast, turning old watchmaker vials into terrarium jewelry. The beautiful pieces all contain a live green specimen of moss. The moss stays alive due to little implementations of charcoal at the bottom of the vial.
The charcoal is supposed to keep the ecosystem healthy and thriving. The terrarium jewelry only needs to be watered (with a drop) every three weeks. The idea behind the jewelry is to keep it thriving, but if it should die, the necklace isn't useless. Erica Weiner just suggests to pick some moss and put it into the terrarium jewelry to start over.