Short answer: the saw and core size set the diameter, the rim depends on whether you need a clean cut or speed, and the bond depends on rock hardness.
Diameter
A 300 mm blade fits most core saws and NQ and HQ core. A 350 mm blade gives more cutting depth for large PQ core. Check which diameter your saw is designed for.
Rim
- Continuous: clean cut, minimal chipping. For brittle, fractured core and precise cuts.
- Segmented: faster cutting, better cooling. For hard rock and high volumes.
Bond
The rule is counter-intuitive: hard rock needs a soft bond, which exposes fresh diamonds faster. Soft abrasive rock needs a hard bond, otherwise the blade wears quickly.
Stock and prices on the diamond blades page.