central heating - a heating system in which air or water is heated at a central furnace and sent through the building via vents or pipes and radiators
exists and is an alternate of . Five physical characteristics of a mineral are: hardness, luster, diaphaneity, colour, and streak.
Amphibole mineralsâ defining characteristics are their dark color, hardness and well-developed cleavage. These usually serve to distinguish them from most other common rock-forming minerals with the exception of the pyroxene mineral group.