Diamond blades are made of a high quality steel core with a matrix around the perimeter composed of synthetic diamonds embedded in a bonding material.
Some diamond blades are designed to run dry in applications
Two broad factors are used to evaluate what particular diamond blades should be used to cut and how long they will last: Type of bond and Style of blade.
The type of bond used to hold the diamonds diamonds varies between different levels of softness and hardness. In addition to giving a base for the diamonds, the bond allows for a specific wear rate to match the material being cut.
Usually bond hardness is the inverse of the hardness of the material. For hard materials such as procelain, the bond should be soft so that it wears down porportionally in order to expose new diamonds and deliver a clean cut.
Ideally all diamond blades would use a soft bond so that new diamonds would be continuously exposed to ensure a clean cut. However, a soft bond also reduces the life of a blade. Consequently, most manufacturers use a hard bond for blades designed for cutting softer materials.
Since most manufacturers do not specify the bonding method, it is important to check the packaging to see what type of cutting is recommended for a particular blade.
As a rule of thumb, if the blade is sparking or bouncing when cutting hard material, a blade with a softer bond is needed. Cutting hard material with a hard bond will glaze the blade and require dressing the blade with a dressing stick or running the blade through soft material such as asphalt to expose more diamonds.