I soldered the tiny sterling silver infinity symbols onto sterling silver posts. I gave them a subtle brushed finish just on the surface. They come with sterling silver backs.
They are about 7X3mm.
The last picture shows all three sizes that I have available, with this pair being the smallest of the three.
They can be found here: http://www.etsy.com/shop/phoebestreasure/search?search_query=infinity&search_type=user_shop_ttt_id_5126316&shopname=phoebestreasure
Have any questions? Contact the shop owner.