Katie Hillier was dubbed by The Guardian as “the most important designer you’ve never heard of” and Hillier prefers it this way. Why? She wants to keep her work exclusive, catering only to a small audience of cool girls. Certainly, one of her coolest designs is this diamond stud single earring made of 14 karat yellow gold. Though beautiful as is, a clasp attachment running through the jewelry encourages you to customize it by clipping on the charm of your choice.