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.
Rocks are naturally formed, consolidated material composed of grains of one or more minerals. Geologists group rocks into three categories depending on their origin: igneous, sedimentary and metamorphic.A mineral is defined as a naturally occurring, crystalline solid of definite chemical composition and a characteristic crystal structure. Igneous rocks are formed from solidification of molten material.eologists group rocks into three categories depending on their origin: igneous, sedimentary and metamorphic. A mineral is defined as a naturally occurring, crystalline solid of definite chemical composition and a characteristic crystal structure.