If you would like a splash of color set in a handsome and traditional buckle collar, this is worth taking a look at.
The Nina Collar with Green Swarovski Crystals (Fits 12"-12 3/4" neck)
Tooled black "English" bridle leather buckle collar with light green Swarovski crystals; 5/8" width tapered to 1/2"; Stainless steel roller buckle and O-ring; Fits 12" - 12 3/4" neck
For sizing, place a flexible tape measure around your dog's neck in the place you would like the collar to rest, and pull it to the appropriate snugness, taking note of the measurement. Be careful to avoid fingers under the measuring tape.
If you have a collar that fits well, you may buckle it on the hole your dog is currently using and take a measurement of the INNER circumference, NOT around the outer perimeter of the collar.