There is no specific grading system for Yerevan Basalt in Armenia. Basalt is a type of volcanic rock, and its characteristics, including hardness, composition, and appearance, may vary depending on its specific location and formation process. As a result, basalt can be used for various purposes, including construction, road paving, and decorative uses. The specific grade or quality of basalt would depend on its intended use and the requirements or standards set by the relevant industry or project.