EXCLUSIVE AT NET-A-PORTER. Designers Jia-Jia Zhu and London Harris believe in working with natural minerals. "We allow our intuition and energy to draw us to the ones we work with," they say. This gold necklace has been strung by hand with raw rainbow sapphire beads, along with four milky freshwater pearls and a faceted quartz crystal at its center. The large stone is said to promote mental clarity, so wear it on days when focus is key.