I designed very simple dual color minecraft ore keychain with strong key-ring hole.
Should be easy to just put on any default sized key rings
I used it with ordinary 25mm keyring (see in photo)
Dimmensions of ore are 19 x 21.5 x 21.5 mm (ore without ring is 19x19x19mm)
In print profile there is diamond like color, but you can change it by changing blue-like color to your wished color in slicer (or just hit PRINT and map your color in AMS screen)