One tiny green glass/crystal stone (Kennington OX1)

I have this brooch that I'm very fond of, although it's nothing special. It features a frog on a lily pad, and unfortunately the frog has lost one of its sparkly green eyes.
I can't find any place to obtain just one tiny stone (max dimension about 1mm diameter) and I don't want to have to buy a pack of several hundred! I wondered if there is any jewellery maker out there who might be able to spare just one stone, or point me to where I might be able to get one.
Thank you!