International Society for Rock Mechanics developed general geotechnical description of rock masses. Aim of this classification is to characterise various regions that constitute a given rock mass. The ISRM classification is not considered as an exhaustive description and needs to be supplement by additional information. It value lies in presenting unambiguous terms as well as the standard interval limits for the parameters considered.

ISRM Classification recommends following characteristics

1. Rock name, with simplified geological description
2. Two structural characteristics
   1. Layer thickness
   2. Discontinuity spacing (fracture intercept)
3. Two mechanical characteristics
   1. Uniaxial compressive strength
   2. Angle of friction of the fractures