La Chiocciolina (Atinuj Tantivit) / Sophie Marie Smith

In her "Ring for Each Finger" series, Thai artist Atinuj Tantivit gives the traditional fourth finger a rest and honours "each [other] finger with its own representative ring." I'm guessing the button represents the pointer and the index cards represent "thumbing" through. But wait... those are thumb tacks, aren't they? While I mull this over, visit her site, La Chiocciolina.

Bonus link:
For rings that I'm 100% certain were made for the thumb, like the one pictured here, see Sophie Marie Smith. The UK jeweller specializes in simple silver pieces.

Even more jewellery:

• Kirsten Kinvara (UK) - black buttons


• Makiko Shinoda (Japan) - conceptual jewellery


• Kemmo (Australia) - wheels & nozzles


• Robyn Kane (Michigan) - contemporary silver


• Nadia Lee Solomon (New York) - gold vermeil